| Abies concolor | (Gordon) Lindl. ex Hildebr. | Pinaceae | 8 |
| Abies religiosa | (Kunth) Schltdl. & Cham. | Pinaceae | 8 |
| Abronia gracilis | Benth. | Nyctaginaceae | 8 |
| Abronia maritima | Nutt. ex S.Watson | Nyctaginaceae | 8 |
| Abronia umbellata | Lam. | Nyctaginaceae | 8 |
| Abronia villosa | S.Watson | Nyctaginaceae | 8 |
| Abutilon abutiloides | (Jacq.) Garcke ex Hochr. | Malvaceae | 8 |
| Abutilon incanum | (Link) Sweet | Malvaceae | 8 |
| Abutilon malacum | S.Watson | Malvaceae | 8 |
| Abutilon mollicomum | (Willd.) Sweet | Malvaceae | 8 |
| Abutilon palmeri | A.Gray | Malvaceae | 8 |
| Abutilon parishii | S.Watson | Malvaceae | 8 |
| Abutilon parvulum | A.Gray | Malvaceae | 8 |
| Abutilon reventum | S.Watson | Malvaceae | 8 |
| Abutilon trisulcatum | Urb. | Malvaceae | 8 |
| Abutilon viscosum | (L.) Dorr | Malvaceae | 8 |
| Abutilon wrightii | A.Gray | Malvaceae | 8 |
| Acaciella angustissima | (Mill.) Britton & Rose | Fabaceae | 8 |
| Acaciella goldmanii | Britton & Rose | Fabaceae | 8 |
| Acalypha alopecuroidea | Jacq. | Euphorbiaceae | 8 |
| Acalypha californica | Benth. | Euphorbiaceae | 8 |
| Acalypha cincta | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha neomexicana | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha persimilis | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha phleoides | Cav. | Euphorbiaceae | 8 |
| Acalypha poiretii | Spreng. | Euphorbiaceae | 8 |
| Acanthocereus tetragonus | (L.) Hummelinck | Cactaceae | 8 |
| Acanthomintha ilicifolia | A.Gray | Lamiaceae | 8 |
| Acer negundo | L. | Sapindaceae | 8 |
| Acer saccharum | Marshall | Sapindaceae | 8 |
| Achillea millefolium | L. | Asteraceae | 8 |
| Achimenes antirrhina | (DC.) C.V.Morton | Gesneriaceae | 8 |
| Achimenes grandiflora | (Schiede) DC. | Gesneriaceae | 8 |
| Achimenes heterophylla | (Mart.) DC. | Gesneriaceae | 8 |
| Achyrachaena mollis | Schauer | Asteraceae | 8 |
| Achyronychia cooperi | A.Gray | Caryophyllaceae | 8 |
| Acleisanthes chenopodioides | (A.Gray) R.A.Levin | Nyctaginaceae | 8 |
| Acleisanthes longiflora | A.Gray | Nyctaginaceae | 8 |
| Acmella radicans | (Jacq.) R.K.Jansen | Asteraceae | 8 |
| Acmella repens | Rich. ex Pers. | Asteraceae | 8 |
| Acmispon argophyllus | (A.Gray) Brouillet | Fabaceae | 8 |
| Acmispon brachycarpus | (Benth.) D.D.Sokoloff | Fabaceae | 8 |
| Acmispon decumbens | (Benth.) Govaerts | Fabaceae | 8 |
| Acmispon dendroideus | (Greene) Brouillet | Fabaceae | 8 |
| Acmispon distichus | (Greene) Brouillet | Fabaceae | 8 |
| Acmispon glaber | (Vogel) Brouillet | Fabaceae | 8 |
| Acmispon grandiflorus | (Benth.) Brouillet | Fabaceae | 8 |
| Acmispon maritimus | (Nutt.) D.D.Sokoloff | Fabaceae | 8 |
| Acmispon micranthus | (Nutt. ex Torr. & A.Gray) Brouillet | Fabaceae | 8 |
| Acmispon neomexicanus | (Greene) Brouillet | Fabaceae | 8 |
| Acmispon niveus | (S.Watson) Brouillet | Fabaceae | 8 |
| Acmispon oroboides | (Kunth) Brouillet | Fabaceae | 8 |
| Acmispon prostratus | (Nutt.) Brouillet | Fabaceae | 8 |
| Acmispon rigidus | (Benth.) Brouillet | Fabaceae | 8 |
| Acmispon strigosus | (Nutt.) Brouillet | Fabaceae | 8 |
| Acmispon tomentosus | (Hook. & Arn.) Govaerts | Fabaceae | 8 |
| Acmispon utahensis | (Ottley) Brouillet | Fabaceae | 8 |
| Acmispon watsonii | (Vasey & Rose) Brouillet | Fabaceae | 8 |
| Acmispon wrangelianus | (Fisch. & C.A.Mey.) Sokoloff | Fabaceae | 8 |
| Aconitum columbianum | Nutt. | Ranunculaceae | 8 |
| Acourtia microcephala | DC. | Asteraceae | 8 |
| Acourtia nana | (A.Gray) Reveal & R.M.King | Asteraceae | 8 |
| Acourtia wislizeni | (A.Gray) Reveal & R.M.King | Asteraceae | 8 |
| Acourtia wrightii | (A.Gray) Reveal & R.M.King | Asteraceae | 8 |
| Adelia brandegeei | V.W.Steinm. | Euphorbiaceae | 8 |
| Adenophyllum porophylloides | (A.Gray) Strother | Asteraceae | 8 |
| Adenophyllum speciosum | (A.Gray) Strother | Asteraceae | 8 |
| Adenostoma fasciculatum | Hook. & Arn. | Rosaceae | 8 |
| Adenostoma sparsifolium | Torr. | Rosaceae | 8 |
| Adiantum aleuticum | (Rupr.) C.A.Paris | Pteridaceae | 8 |
| Adiantum amplum | C.Presl | Pteridaceae | 8 |
| Adiantum andicola | Liebm. | Pteridaceae | 8 |
| Adiantum braunii | Mett. | Pteridaceae | 8 |
| Adiantum capillus-veneris | L. | Pteridaceae | 8 |
| Adiantum concinnum | Humb. & Bonpl. ex Willd. | Pteridaceae | 8 |
| Adiantum jordanii | C.H.Mull. | Pteridaceae | 8 |
| Adiantum poiretii | Wikstr. | Pteridaceae | 8 |
| Adiantum tricholepis | Fée | Pteridaceae | 8 |
| Adolphia californica | S.Watson | Rhamnaceae | 8 |
| Adolphia infesta | (Kunth) Meisn. | Rhamnaceae | 8 |
| Aeschynomene americana | L. | Fabaceae | 8 |
| Aeschynomene villosa | Poir. | Fabaceae | 8 |
| Aesculus parryi | A.Gray | Sapindaceae | 8 |
| Agastache pallida | (Lindl.) Cory | Lamiaceae | 8 |
| Agave americana | L. | Asparagaceae | 8 |
| Agave angustifolia | Haw. | Asparagaceae | 8 |
| Agave attenuata | Salm-Dyck | Asparagaceae | 8 |
| Agave aurea | Brandegee | Asparagaceae | 8 |
| Agave azurea | R.H.Webb & G.D.Starr | Asparagaceae | 8 |
| Agave deserti | Engelm. | Asparagaceae | 8 |
| Agave palmeri | Engelm. | Asparagaceae | 8 |
| Agave parryi | Engelm. | Asparagaceae | 8 |
| Agave schidigera | Lem. | Asparagaceae | 8 |
| Agave schottii | Engelm. | Asparagaceae | 8 |
| Agave sebastiana | Greene | Asparagaceae | 8 |
| Agave shawii | Engelm. | Asparagaceae | 8 |
| Agave shrevei | Gentry | Asparagaceae | 8 |
| Agave vilmoriniana | A.Berger | Asparagaceae | 8 |
| Ageratina adenophora | (Spreng.) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina areolaris | (DC.) D.Gage ex B.L.Turner | Asteraceae | 8 |
| Ageratina glabrata | (Kunth) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina herbacea | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina mairetiana | (DC.) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina paupercula | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina pichinchensis | (Kunth) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina rothrockii | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratum conyzoides | L. | Asteraceae | 8 |
| Ageratum corymbosum | Zucc. ex Pers. | Asteraceae | 8 |
| Agonandra racemosa | (DC.) Standl. | Opiliaceae | 8 |
| Agoseris grandiflora | (Nutt.) Greene | Asteraceae | 8 |
| Agoseris heterophylla | (Nutt.) Greene | Asteraceae | 8 |
| Agoseris retrorsa | Greene | Asteraceae | 8 |
| Agrimonia striata | Michx. | Rosaceae | 8 |
| Agrostis hyemalis | (Walter) Britton, Sterns & Poggenb. | Poaceae | 8 |
| Agrostis pallens | Trin. | Poaceae | 8 |
| Agrostis scabra | Willd. | Poaceae | 8 |
| Alchemilla occidentalis | Nutt. | Rosaceae | 8 |
| Aldama cordifolia | (A.Gray) E.E.Schill. & Panero | Asteraceae | 8 |
| Aldama dentata | La Llave | Asteraceae | 8 |
| Aliciella latifolia | (S.Watson) J.M.Porter | Polemoniaceae | 8 |
| Alisma triviale | Pursh | Alismataceae | 8 |
| Allenrolfea occidentalis | (S.Watson) Kuntze | Chenopodiaceae | 8 |
| Allionia choisyi | Standl. | Nyctaginaceae | 8 |
| Allionia incarnata | L. | Nyctaginaceae | 8 |
| Allium fimbriatum | S.Watson | Amaryllidaceae | 8 |
| Allium haematochiton | S.Watson | Amaryllidaceae | 8 |
| Allium longifolium | (Kunth) Spreng. | Amaryllidaceae | 8 |
| Allium macropetalum | Rydb. | Amaryllidaceae | 8 |
| Allium parryi | S.Watson | Amaryllidaceae | 8 |
| Allium peninsulare | Lemmon ex Greene | Amaryllidaceae | 8 |
| Allium praecox | Brandegee | Amaryllidaceae | 8 |
| Allium rhizomatum | Wooton & Standl. | Amaryllidaceae | 8 |
| Allium unifolium | Kellogg | Amaryllidaceae | 8 |
| Alloispermum integrifolium | (DC.) H.Rob. | Asteraceae | 8 |
| Allophyllum gilioides | (Benth.) A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Allophyllum glutinosum | (Benth.) A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Allowissadula holosericea | (Scheele) D.M.Bates | Malvaceae | 8 |
| Alnus acuminata | Kunth | Betulaceae | 8 |
| Alnus jorullensis | Kunth | Betulaceae | 8 |
| Alnus oblongifolia | Torr. | Betulaceae | 8 |
| Alnus rhombifolia | Nutt. | Betulaceae | 8 |
| Alopecurus aequalis | Sobol. | Poaceae | 8 |
| Alopecurus carolinianus | Walter | Poaceae | 8 |
| Alopecurus saccatus | Vasey | Poaceae | 8 |
| Aloysia gratissima | (Gillies & Hook.) Tronc. | Verbenaceae | 8 |
| Aloysia wrightii | A.Heller | Verbenaceae | 8 |
| Alternanthera caracasana | Kunth | Amaranthaceae | 8 |
| Alternanthera paronychioides | A.St.-Hil. | Amaranthaceae | 8 |
| Alternanthera pungens | Kunth | Amaranthaceae | 8 |
| Alternanthera pycnantha | (Benth.) Standl. | Amaranthaceae | 8 |
| Alvaradoa amorphoides | Liebm. | Picramniaceae | 8 |
| Amaranthus fimbriatus | (Torr.) Benth. ex S.Watson | Amaranthaceae | 8 |
| Amaranthus hypochondriacus | L. | Amaranthaceae | 8 |
| Amaranthus palmeri | S.Watson | Amaranthaceae | 8 |
| Amaranthus polygonoides | L. | Amaranthaceae | 8 |
| Amaranthus powellii | S.Watson | Amaranthaceae | 8 |
| Amaranthus spinosus | L. | Amaranthaceae | 8 |
| Amaranthus watsonii | Standl. | Amaranthaceae | 8 |
| Amauria rotundifolia | Benth. | Asteraceae | 8 |
| Amblyopappus pusillus | Hook. & Arn. | Asteraceae | 8 |
| Ambrosia acanthicarpa | Hook. | Asteraceae | 8 |
| Ambrosia ambrosioides | (Delpino) W.W.Payne | Asteraceae | 8 |
| Ambrosia bryantii | (Curran) W.W.Payne | Asteraceae | 8 |
| Ambrosia camphorata | (Greene) W.W.Payne | Asteraceae | 8 |
| Ambrosia chamissonis | Greene | Asteraceae | 8 |
| Ambrosia chenopodiifolia | (Benth.) W.W.Payne | Asteraceae | 8 |
| Ambrosia confertiflora | DC. | Asteraceae | 8 |
| Ambrosia cordifolia | (A.Gray) W.W.Payne | Asteraceae | 8 |
| Ambrosia deltoidea | (Torr.) W.W.Payne | Asteraceae | 8 |
| Ambrosia dumosa | (A.Gray) W.W.Payne | Asteraceae | 8 |
| Ambrosia ilicifolia | (A.Gray) W.W.Payne | Asteraceae | 8 |
| Ambrosia magdalenae | (Brandegee) W.W.Payne | Asteraceae | 8 |
| Ambrosia psilostachya | DC. | Asteraceae | 8 |
| Ambrosia pumila | (Nutt.) A.Gray | Asteraceae | 8 |
| Ambrosia trifida | L. | Asteraceae | 8 |
| Amelanchier utahensis | Koehne | Rosaceae | 8 |
| Amicia zygomeris | DC. | Fabaceae | 8 |
| Ammannia auriculata | Willd. | Lythraceae | 8 |
| Ammannia coccinea | Rottb. | Lythraceae | 8 |
| Ammannia robusta | Heer & Regel | Lythraceae | 8 |
| Amorpha californica | Nutt. | Fabaceae | 8 |
| Amorpha fruticosa | L. | Fabaceae | 8 |
| Ampelocissus acapulcensis | (Kunth) Planch. | Vitaceae | 8 |
| Ampelopsis cordata | Michx. | Vitaceae | 8 |
| Ampelopsis denudata | Planch. | Vitaceae | 8 |
| Amphilophium crucigerum | (L.) L.G.Lohmann | Bignoniaceae | 8 |
| Amphilophium paniculatum | (L.) Kunth | Bignoniaceae | 8 |
| Amsinckia eastwoodiae | J.F.Macbr. | Boraginaceae | 8 |
| Amsinckia inepta | J.F.Macbr. | Boraginaceae | 8 |
| Amsinckia menziesii | (Lehm.) A.Nelson & J.F.Macbr. | Boraginaceae | 8 |
| Amsinckia spectabilis | Fisch. & C.A.Mey. | Boraginaceae | 8 |
| Amsinckia tessellata | A.Gray | Boraginaceae | 8 |
| Amsonia palmeri | A.Gray | Apocynaceae | 8 |
| Anaphalis margaritacea | (L.) Benth. & Hook.f. | Asteraceae | 8 |
| Ancistrocarphus filagineus | A.Gray | Asteraceae | 8 |
| Andira inermis | (W.Wright) Kunth ex DC. | Fabaceae | 8 |
| Andropogon cirratus | Hack. | Poaceae | 8 |
| Androsace elongata | L. | Primulaceae | 8 |
| Androsace occidentalis | Pursh | Primulaceae | 8 |
| Androsace septentrionalis | L. | Primulaceae | 8 |
| Anemia tomentosa | (Savigny) Sw. | Anemiaceae | 8 |
| Anemone tuberosa | Rydb. | Ranunculaceae | 8 |
| Anemopsis californica | (Nutt.) Hook. & Arn. | Saururaceae | 8 |
| Angelica capitellata | (A.Gray) Spalik, Reduron & S.R.Downie | Apiaceae | 8 |
| Anisacanthus thurberi | (Torr.) A.Gray | Acanthaceae | 8 |
| Anisocoma acaulis | Torr. & A.Gray | Asteraceae | 8 |
| Annona reticulata | L. | Annonaceae | 8 |
| Annona squamosa | L. | Annonaceae | 8 |
| Anoda acerifolia | Cav. | Malvaceae | 8 |
| Anoda crenatiflora | Ortega | Malvaceae | 8 |
| Anoda cristata | (L.) Schltdl. | Malvaceae | 8 |
| Anoda lanceolata | Hook. & Arn. | Malvaceae | 8 |
| Anoda pentaschista | A.Gray | Malvaceae | 8 |
| Anogramma leptophylla | (L.) Link | Pteridaceae | 8 |
| Anredera vesicaria | (Lam.) C.F.Gaertn. | Basellaceae | 8 |
| Antennaria marginata | Greene | Asteraceae | 8 |
| Antennaria parvifolia | Nutt. | Asteraceae | 8 |
| Anticlea virescens | (Kunth) Rydb. | Melanthiaceae | 8 |
| Antigonon leptopus | Hook. & Arn. | Polygonaceae | 8 |
| Aphanisma blitoides | Nutt. ex Moq. | Chenopodiaceae | 8 |
| Apiastrum angustifolium | Nutt. | Apiaceae | 8 |
| Apocynum cannabinum | L. | Apocynaceae | 8 |
| Apodanthera undulata | A.Gray | Cucurbitaceae | 8 |
| Aquilegia chrysantha | A.Gray | Ranunculaceae | 8 |
| Aquilegia elegantula | Greene | Ranunculaceae | 8 |
| Aquilegia formosa | Fisch. ex DC. | Ranunculaceae | 8 |
| Aquilegia longissima | A.Gray ex S.Watson | Ranunculaceae | 8 |
| Arachnothryx leucophylla | (Kunth) Planch. | Rubiaceae | 8 |
| Aralia bicrenata | Wooton & Standl. | Araliaceae | 8 |
| Aralia humilis | Cav. | Araliaceae | 8 |
| Arbutus arizonica | (A.Gray) Sarg. | Ericaceae | 8 |
| Arbutus bicolor | S.González, M.González & P.D.Sørensen | Ericaceae | 8 |
| Arbutus madrensis | S.González | Ericaceae | 8 |
| Arbutus menziesii | Pursh | Ericaceae | 8 |
| Arbutus occidentalis | McVaugh & Rosatti | Ericaceae | 8 |
| Arbutus tessellata | P.D.Sørensen | Ericaceae | 8 |
| Arbutus xalapensis | Kunth | Ericaceae | 8 |
| Arceuthobium campylopodum | Engelm. | Santalaceae | 8 |
| Arceuthobium divaricatum | Engelm. | Santalaceae | 8 |
| Arceuthobium douglasii | Engelm. | Santalaceae | 8 |
| Arceuthobium globosum | Hawksw. & Wiens | Santalaceae | 8 |
| Arceuthobium vaginatum | (Humb. & Bonpl. ex Willd.) J.Presl | Santalaceae | 8 |
| Archibaccharis serratifolia | S.F.Blake | Asteraceae | 8 |
| Arctostaphylos glandulosa | Eastw. | Ericaceae | 8 |
| Arctostaphylos glauca | Lindl. | Ericaceae | 8 |
| Arctostaphylos otayensis | Wiesl. & B.Schreib. | Ericaceae | 8 |
| Arctostaphylos parryana | Lemmon | Ericaceae | 8 |
| Arctostaphylos patula | Greene | Ericaceae | 8 |
| Arctostaphylos pringlei | Parry | Ericaceae | 8 |
| Arctostaphylos pungens | Kunth | Ericaceae | 8 |
| Ardisia compressa | Kunth | Primulaceae | 8 |
| Ardisia revoluta | Kunth | Primulaceae | 8 |
| Arenaria lanuginosa | (Michx.) Rohrb. | Caryophyllaceae | 8 |
| Arenaria paludicola | B.L.Rob. | Caryophyllaceae | 8 |
| Argemone grandiflora | Sweet | Papaveraceae | 8 |
| Argemone munita | Durand & Hilg. | Papaveraceae | 8 |
| Argemone ochroleuca | Sweet | Papaveraceae | 8 |
| Argemone platyceras | Link & Otto | Papaveraceae | 8 |
| Argemone pleiacantha | Greene | Papaveraceae | 8 |
| Argentina anserina | (L.) Rydb. | Rosaceae | 8 |
| Argyrochosma jonesii | (Maxon) Windham | Pteridaceae | 8 |
| Argyrochosma limitanea | (Maxon) Windham | Pteridaceae | 8 |
| Argyrochosma microphylla | (Kuhn) Windham | Pteridaceae | 8 |
| Aristida adscensionis | L. | Poaceae | 8 |
| Aristida arizonica | Vasey | Poaceae | 8 |
| Aristida divaricata | Humb. & Bonpl. ex Willd. | Poaceae | 8 |
| Aristida purpurea | Nutt. | Poaceae | 8 |
| Aristida ternipes | Cav. | Poaceae | 8 |
| Aristolochia taliscana | Hook. & Arn. | Aristolochiaceae | 8 |
| Aristolochia watsonii | Wooton & Standl. | Aristolochiaceae | 8 |
| Artemisia californica | Less. | Asteraceae | 8 |
| Artemisia carruthii | Alph.Wood ex J.H.Carruth | Asteraceae | 8 |
| Artemisia douglasiana | Besser | Asteraceae | 8 |
| Artemisia dracunculus | L. | Asteraceae | 8 |
| Artemisia ludoviciana | Nutt. | Asteraceae | 8 |
| Artemisia palmeri | A.Gray | Asteraceae | 8 |
| Artemisia tridentata | Nutt. | Asteraceae | 8 |
| Asclepias albicans | S.Watson | Apocynaceae | 8 |
| Asclepias angustifolia | Schweigg. | Apocynaceae | 8 |
| Asclepias asperula | (Decne.) Woodson | Apocynaceae | 8 |
| Asclepias brachystephana | Engelm. ex Torr. | Apocynaceae | 8 |
| Asclepias curassavica | L. | Apocynaceae | 8 |
| Asclepias engelmanniana | Woodson | Apocynaceae | 8 |
| Asclepias eriocarpa | Benth. | Apocynaceae | 8 |
| Asclepias erosa | Torr. | Apocynaceae | 8 |
| Asclepias fascicularis | Decne. | Apocynaceae | 8 |
| Asclepias fournieri | Woodson | Apocynaceae | 8 |
| Asclepias hypoleuca | (A.Gray) Woodson | Apocynaceae | 8 |
| Asclepias involucrata | Engelm. ex Torr. | Apocynaceae | 8 |
| Asclepias lemmonii | A.Gray | Apocynaceae | 8 |
| Asclepias linaria | Cav. | Apocynaceae | 8 |
| Asclepias nummularia | Torr. | Apocynaceae | 8 |
| Asclepias nyctaginifolia | A.Gray | Apocynaceae | 8 |
| Asclepias oenotheroides | Schltdl. & Cham. | Apocynaceae | 8 |
| Asclepias otarioides | E.Fourn. | Apocynaceae | 8 |
| Asclepias rusbyi | (Vail) Woodson | Apocynaceae | 8 |
| Asclepias subulata | Decne. | Apocynaceae | 8 |
| Asclepias subverticillata | (A.Gray) Vail | Apocynaceae | 8 |
| Asclepias tuberosa | L. | Apocynaceae | 8 |
| Aspicarpa albida | (Cham. & Schltdl.) Hassl. | Malpighiaceae | 8 |
| Aspicarpa cynanchoides | (Kunth) Hassl. | Malpighiaceae | 8 |
| Aspicarpa hirtella | Rich. | Malpighiaceae | 8 |
| Aspidotis californica | (Hook.) Nutt. ex Copel. | Pteridaceae | 8 |
| Asplenium adiantum-nigrum | L. | Aspleniaceae | 8 |
| Asplenium fragrans | Sw. | Aspleniaceae | 8 |
| Asplenium monanthes | L. | Aspleniaceae | 8 |
| Asplenium praemorsum | Sw. | Aspleniaceae | 8 |
| Asplenium resiliens | Kunze | Aspleniaceae | 8 |
| Asplenium septentrionale | (L.) Hoffm. | Aspleniaceae | 8 |
| Asplenium vespertinum | Maxon | Aspleniaceae | 8 |
| Aster moranensis | Kunth | Asteraceae | 8 |
| Asterohyptis stellulata | (Benth.) Epling | Lamiaceae | 8 |
| Astraea lobata | (L.) Klotzsch | Euphorbiaceae | 8 |
| Astragalus acutirostris | S.Watson | Fabaceae | 8 |
| Astragalus allochrous | A.Gray | Fabaceae | 8 |
| Astragalus anemophilus | Greene | Fabaceae | 8 |
| Astragalus aridus | A.Gray | Fabaceae | 8 |
| Astragalus brauntonii | Parish | Fabaceae | 8 |
| Astragalus circumdatus | Greene | Fabaceae | 8 |
| Astragalus cobrensis | A.Gray | Fabaceae | 8 |
| Astragalus coccineus | (Parry) Brandegee | Fabaceae | 8 |
| Astragalus crotalariae | (Benth.) A.Gray | Fabaceae | 8 |
| Astragalus didymocarpus | Hook. & Arn. | Fabaceae | 8 |
| Astragalus douglasii | (Torr. & A.Gray) A.Gray | Fabaceae | 8 |
| Astragalus filipes | Torr. ex A.Gray | Fabaceae | 8 |
| Astragalus gambelianus | E.Sheld. | Fabaceae | 8 |
| Astragalus gruinus | Barneby | Fabaceae | 8 |
| Astragalus humistratus | A.Gray | Fabaceae | 8 |
| Astragalus idrietorum | Barneby | Fabaceae | 8 |
| Astragalus lentiginosus | Douglas ex Hook. | Fabaceae | 8 |
| Astragalus magdalenae | Greene | Fabaceae | 8 |
| Astragalus mollissimus | Torr. | Fabaceae | 8 |
| Astragalus nothoxys | A.Gray | Fabaceae | 8 |
| Astragalus nuttallianus | DC. | Fabaceae | 8 |
| Astragalus palmeri | A.Gray | Fabaceae | 8 |
| Astragalus pomonensis | M.E.Jones | Fabaceae | 8 |
| Astragalus sabulonum | A.Gray | Fabaceae | 8 |
| Astragalus tephrodes | A.Gray | Fabaceae | 8 |
| Astragalus thurberi | A.Gray | Fabaceae | 8 |
| Astragalus trichopodus | (Nutt.) A.Gray | Fabaceae | 8 |
| Astragalus wootonii | E.Sheld. | Fabaceae | 8 |
| Astrolepis cochisensis | (Goodd.) D.M.Benham & Windham | Pteridaceae | 8 |
| Astrolepis integerrima | (Hook.) D.M.Benham & Windham | Pteridaceae | 8 |
| Astrolepis sinuata | (Lag. ex Sw.) D.M.Benham & Windham | Pteridaceae | 8 |
| Astrolepis windhamii | D.M.Benham | Pteridaceae | 8 |
| Athysanus pusillus | Greene | Brassicaceae | 8 |
| Atrichoseris platyphylla | (A.Gray) A.Gray | Asteraceae | 8 |
| Atriplex acanthocarpa | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex barclayana | (Benth.) D.Dietr. | Chenopodiaceae | 8 |
| Atriplex canescens | (Pursh) Nutt. | Chenopodiaceae | 8 |
| Atriplex elegans | (Moq.) D.Dietr. | Chenopodiaceae | 8 |
| Atriplex hymenelytra | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex julacea | S.Watson | Chenopodiaceae | 8 |
| Atriplex lentiformis | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex leucophylla | (Moq.) D.Dietr. | Chenopodiaceae | 8 |
| Atriplex pacifica | A.Nelson | Chenopodiaceae | 8 |
| Atriplex parishii | S.Watson | Chenopodiaceae | 8 |
| Atriplex polycarpa | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex watsonii | A.Nelson ex Abrams | Chenopodiaceae | 8 |
| Avicennia germinans | (L.) L. | Acanthaceae | 8 |
| Axonopus compressus | (Sw.) P.Beauv. | Poaceae | 8 |
| Ayenia aculeata | (Jacq.) Christenh. & Byng | Malvaceae | 8 |
| Ayenia compacta | Rose | Malvaceae | 8 |
| Ayenia filiformis | S.Watson | Malvaceae | 8 |
| Ayenia micrantha | Standl. | Malvaceae | 8 |
| Ayenia microphylla | A.Gray | Malvaceae | 8 |
| Azolla filiculoides | Lam. | Salviniaceae | 8 |
| Baccharis brachyphylla | A.Gray | Asteraceae | 8 |
| Baccharis heterophylla | Kunth | Asteraceae | 8 |
| Baccharis neglecta | Britton | Asteraceae | 8 |
| Baccharis pilularis | DC. | Asteraceae | 8 |
| Baccharis pteronioides | DC. | Asteraceae | 8 |
| Baccharis salicifolia | (Ruiz & Pav.) Pers. | Asteraceae | 8 |
| Baccharis salicina | Torr. & A.Gray | Asteraceae | 8 |
| Baccharis sarothroides | A.Gray | Asteraceae | 8 |
| Baccharis sergiloides | A.Gray | Asteraceae | 8 |
| Baccharis thesioides | Kunth | Asteraceae | 8 |
| Baccharis trinervis | Pers. | Asteraceae | 8 |
| Baccharis wrightii | A.Gray | Asteraceae | 8 |
| Bacopa monnieri | (L.) Wettst. | Plantaginaceae | 8 |
| Baileya pauciradiata | Harv. & A.Gray | Asteraceae | 8 |
| Baileya pleniradiata | Harv. & A.Gray | Asteraceae | 8 |
| Barbarea orthoceras | Ledeb. | Brassicaceae | 8 |
| Barkleyanthus salicifolius | (Kunth) H.Rob. & Brettell | Asteraceae | 8 |
| Batis maritima | L. | Bataceae | 8 |
| Bauhinia divaricata | L. | Fabaceae | 8 |
| Bauhinia ungulata | L. | Fabaceae | 8 |
| Bebbia juncea | Greene | Asteraceae | 8 |
| Begonia angustiloba | A.DC. | Begoniaceae | 8 |
| Begonia balmisiana | F.X.d.Bálmis | Begoniaceae | 8 |
| Begonia gracilis | Kunth | Begoniaceae | 8 |
| Begonia heracleifolia | Schltdl. & Cham. | Begoniaceae | 8 |
| Begonia tapatia | Burt-Utley & McVaugh | Begoniaceae | 8 |
| Bejaria aestuans | Mutis | Ericaceae | 8 |
| Berberis dictyota | Jeps. | Berberidaceae | 8 |
| Berberis fremontii | Torr. | Berberidaceae | 8 |
| Berberis haematocarpa | Wooton | Berberidaceae | 8 |
| Berberis pinnata | Lag. | Berberidaceae | 8 |
| Berberis trifoliolata | Moric. | Berberidaceae | 8 |
| Berberis wilcoxii | Kearney | Berberidaceae | 8 |
| Bergerocactus emoryi | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Berlandiera lyrata | Benth. | Asteraceae | 8 |
| Bernardia incana | C.V.Morton | Euphorbiaceae | 8 |
| Bernardia myricifolia | (Scheele) S.Watson | Euphorbiaceae | 8 |
| Bernardia obovata | I.M.Johnst. | Euphorbiaceae | 8 |
| Bernardia viridis | Millsp. | Euphorbiaceae | 8 |
| Bessera elegans | Schult.f. | Asparagaceae | 8 |
| Bessera tenuiflora | (Greene) J.F.Macbr. | Asparagaceae | 8 |
| Bidens alba | DC. | Asteraceae | 8 |
| Bidens aurea | (Aiton) Sherff | Asteraceae | 8 |
| Bidens bigelovii | A.Gray | Asteraceae | 8 |
| Bidens laevis | (L.) Britton, Sterns & Poggenb. | Asteraceae | 8 |
| Bidens leptocephala | Sherff | Asteraceae | 8 |
| Bidens ostruthioides | Sch.Bip. | Asteraceae | 8 |
| Bidens pilosa | L. | Asteraceae | 8 |
| Bidens reptans | G.Don | Asteraceae | 8 |
| Bidens tenuisecta | A.Gray | Asteraceae | 8 |
| Bidens triplinervia | Kunth | Asteraceae | 8 |
| Bidens xanti | (A.Gray) B.L.Turner | Asteraceae | 8 |
| Bignonia aequinoctialis | L. | Bignoniaceae | 8 |
| Billbergia pallidiflora | Liebm. | Bromeliaceae | 8 |
| Bixa orellana | L. | Bixaceae | 8 |
| Blechnum appendiculatum | Willd. | Blechnaceae | 8 |
| Bletia campanulata | Lex. | Orchidaceae | 8 |
| Bletia mexicana | (Greenm.) Sosa & M.W.Chase | Orchidaceae | 8 |
| Bletia nitida | (L.O.Williams) Sosa & M.W.Chase | Orchidaceae | 8 |
| Bletia purpurata | A.Rich. & Galeotti | Orchidaceae | 8 |
| Bletia roezlii | Rchb.f. | Orchidaceae | 8 |
| Bletia warnockii | (Ames & Correll) Sosa & M.W.Chase | Orchidaceae | 8 |
| Blitum californicum | S.Watson | Chenopodiaceae | 8 |
| Blitum nuttallianum | Schult. | Chenopodiaceae | 8 |
| Bloomeria clevelandii | S.Watson | Asparagaceae | 8 |
| Bloomeria crocea | (Torr.) Coville | Asparagaceae | 8 |
| Blumea viscosa | (Mill.) V.M.Badillo | Asteraceae | 8 |
| Bocconia arborea | S.Watson | Papaveraceae | 8 |
| Bocconia frutescens | L. | Papaveraceae | 8 |
| Boeberastrum anthemidifolium | Rydb. | Asteraceae | 8 |
| Boechera californica | (Rollins) Windham & Al-Shehbaz | Brassicaceae | 8 |
| Boechera perennans | (S.Watson) W.A.Weber | Brassicaceae | 8 |
| Boechera pulchra | (M.E.Jones ex S.Watson) W.A.Weber | Brassicaceae | 8 |
| Boerhavia brandegeei | (Standl.) Govaerts | Nyctaginaceae | 8 |
| Boerhavia coccinea | Mill. | Nyctaginaceae | 8 |
| Boerhavia coulteri | (Hook.f.) S.Watson | Nyctaginaceae | 8 |
| Boerhavia erecta | L. | Nyctaginaceae | 8 |
| Boerhavia gracillima | Heimerl | Nyctaginaceae | 8 |
| Boerhavia linearifolia | A.Gray | Nyctaginaceae | 8 |
| Boerhavia purpurascens | A.Gray | Nyctaginaceae | 8 |
| Boerhavia scandens | L. | Nyctaginaceae | 8 |
| Boerhavia triquetra | S.Watson | Nyctaginaceae | 8 |
| Boerhavia wrightii | A.Gray | Nyctaginaceae | 8 |
| Bolboschoenus maritimus | (L.) Palla | Cyperaceae | 8 |
| Bolboschoenus robustus | (Pursh) Soják | Cyperaceae | 8 |
| Bommeria hispida | Underw. | Pteridaceae | 8 |
| Bommeria pedata | (Sw.) Fourn. | Pteridaceae | 8 |
| Bonellia macrocarpa | (Cav.) B.Ståhl & Källersjö | Primulaceae | 8 |
| Bonplandia geminiflora | Cav. | Polemoniaceae | 8 |
| Bothriochloa barbinodis | (Lag.) Herter | Poaceae | 8 |
| Bothriochloa torreyana | (Steud.) Scrivanti & Anton | Poaceae | 8 |
| Botrypus virginianus | (L.) Michx. | Ophioglossaceae | 8 |
| Bouchea prismatica | (L.) Kuntze | Verbenaceae | 8 |
| Bouchetia erecta | Dunal | Solanaceae | 8 |
| Bourreria sonorae | S.Watson | Ehretiaceae | 8 |
| Bouteloua aristidoides | (Kunth) Griseb. | Poaceae | 8 |
| Bouteloua barbata | Lag. | Poaceae | 8 |
| Bouteloua chondrosioides | (Kunth) Benth. ex S.Watson | Poaceae | 8 |
| Bouteloua curtipendula | (Michx.) Torr. | Poaceae | 8 |
| Bouteloua eriopoda | (Torr.) Torr. | Poaceae | 8 |
| Bouteloua gracilis | (Kunth) Lag. ex Griffiths | Poaceae | 8 |
| Bouteloua hirsuta | Lag. | Poaceae | 8 |
| Bouteloua parryi | (E.Fourn.) Griffiths | Poaceae | 8 |
| Bouteloua pectinata | Feath. | Poaceae | 8 |
| Bouteloua polymorpha | (E.Fourn.) Columbus | Poaceae | 8 |
| Bouteloua repens | (Kunth) Scribn. & Merr. | Poaceae | 8 |
| Bouteloua rigidiseta | (Steud.) Hitchc. | Poaceae | 8 |
| Bouteloua trifida | Thurb. ex S.Watson | Poaceae | 8 |
| Bouteloua warnockii | Gould & Kapadia | Poaceae | 8 |
| Bouvardia ternifolia | (Cav.) Schltdl. | Rubiaceae | 8 |
| Bowlesia incana | Ruiz & Pav. | Apiaceae | 8 |
| Boykinia rotundifolia | Parry ex A.Gray | Saxifragaceae | 8 |
| Brahea armata | S.Watson | Arecaceae | 8 |
| Brahea brandegeei | (Purpus) H.E.Moore | Arecaceae | 8 |
| Brahea dulcis | (Kunth) Mart. | Arecaceae | 8 |
| Brandegea bigelovii | (S.Watson) Cogn. | Cucurbitaceae | 8 |
| Brickellia atractyloides | A.Gray | Asteraceae | 8 |
| Brickellia baccharidea | A.Gray | Asteraceae | 8 |
| Brickellia betonicifolia | A.Gray | Asteraceae | 8 |
| Brickellia coulteri | A.Gray | Asteraceae | 8 |
| Brickellia desertorum | Coville | Asteraceae | 8 |
| Brickellia frutescens | A.Gray | Asteraceae | 8 |
| Brickellia grandiflora | Nutt. | Asteraceae | 8 |
| Brickellia leptophylla | (Scheele) Shinn. | Asteraceae | 8 |
| Brickellia peninsularis | Brandegee | Asteraceae | 8 |
| Brickellia rusbyi | A.Gray | Asteraceae | 8 |
| Brickellia veronicaefolia | (Kunth) A.Gray | Asteraceae | 8 |
| Brickelliastrum fendleri | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Brodiaea jolonensis | Eastw. | Asparagaceae | 8 |
| Brodiaea orcuttii | (Greene) Baker | Asparagaceae | 8 |
| Brodiaea terrestris | Kellogg | Asparagaceae | 8 |
| Bromelia karatas | L. | Bromeliaceae | 8 |
| Bromelia pinguin | L. | Bromeliaceae | 8 |
| Bromus anomalus | Rupr. ex E.Fourn. | Poaceae | 8 |
| Bromus carinatus | Hook. & Arn. | Poaceae | 8 |
| Brosimum alicastrum | Sw. | Moraceae | 8 |
| Buchnera pusilla | Kunth | Orobanchaceae | 8 |
| Buddleja cordata | Kunth | Scrophulariaceae | 8 |
| Buddleja sessiliflora | Kunth | Scrophulariaceae | 8 |
| Bulbostylis capillaris | (L.) Kunth ex C.B.Clarke | Cyperaceae | 8 |
| Bunchosia palmeri | S.Watson | Malpighiaceae | 8 |
| Bursera bipinnata | (Moc. & Sessé ex DC.) Engl. | Burseraceae | 8 |
| Bursera epinnata | (Rose) Engl. | Burseraceae | 8 |
| Bursera excelsa | (Kunth) Engl. | Burseraceae | 8 |
| Bursera exequielii | León de la Luz | Burseraceae | 8 |
| Bursera fagaroides | (Kunth) Engl. | Burseraceae | 8 |
| Bursera filicifolia | Brandegee | Burseraceae | 8 |
| Bursera grandifolia | (Schltdl.) Engl. | Burseraceae | 8 |
| Bursera hindsiana | (Benth.) Engl. | Burseraceae | 8 |
| Bursera kerberi | Engl. | Burseraceae | 8 |
| Bursera lancifolia | (Schltdl.) Engl. | Burseraceae | 8 |
| Bursera littoralis | León de la Luz & Pérez Navarro | Burseraceae | 8 |
| Bursera microphylla | A.Gray | Burseraceae | 8 |
| Bursera multijuga | Engl. | Burseraceae | 8 |
| Bursera palmeri | S.Watson | Burseraceae | 8 |
| Bursera penicillata | (Sessé & Moc. ex DC.) Engl. | Burseraceae | 8 |
| Bursera simaruba | (L.) Sarg. | Burseraceae | 8 |
| Byrsonima crassifolia | (L.) Kunth | Malpighiaceae | 8 |
| Calandrinia breweri | S.Watson | Montiaceae | 8 |
| Calandrinia ciliata | (Ruiz & Pav.) DC. | Montiaceae | 8 |
| Calceolaria mexicana | Benth. | Calceolariaceae | 8 |
| Calea urticifolia | (Mill.) DC. | Asteraceae | 8 |
| California macrophylla | (Hook. & Arn.) Aldasoro, C.Navarro, P.Vargas, L.Sáez & Aedo | Geraniaceae | 8 |
| Callaeum macropterum | (DC.) D.M.Johnson | Malpighiaceae | 8 |
| Calliandra californica | Benth. | Fabaceae | 8 |
| Calliandra calothyrsus | Meisn. | Fabaceae | 8 |
| Calliandra eriophylla | Benth. | Fabaceae | 8 |
| Calliandra houstoniana | (Mill.) Standl. | Fabaceae | 8 |
| Calliandra humilis | Benth. | Fabaceae | 8 |
| Callianthe purpusii | (Standl.) Donnell | Malvaceae | 8 |
| Callisia repens | (Jacq.) L. | Commelinaceae | 8 |
| Callitriche heterophylla | Pursh | Plantaginaceae | 8 |
| Callitriche palustris | L. | Plantaginaceae | 8 |
| Calocedrus decurrens | (Torr.) Florin | Cupressaceae | 8 |
| Calochortus albus | (Benth.) Douglas ex Benth. | Liliaceae | 8 |
| Calochortus ambiguus | (M.E.Jones) Ownbey | Liliaceae | 8 |
| Calochortus barbatus | (Kunth) Painter | Liliaceae | 8 |
| Calochortus dunnii | Purdy | Liliaceae | 8 |
| Calochortus flexuosus | S.Watson | Liliaceae | 8 |
| Calochortus kennedyi | Porter | Liliaceae | 8 |
| Calochortus splendens | Douglas ex Benth. | Liliaceae | 8 |
| Calochortus weedii | Alph.Wood | Liliaceae | 8 |
| Calopogonium mucunoides | Desv. | Fabaceae | 8 |
| Calycoseris parryi | A.Gray | Asteraceae | 8 |
| Calycoseris wrightii | A.Gray | Asteraceae | 8 |
| Calyptocarpus vialis | Less. | Asteraceae | 8 |
| Calystegia longipes | (S.Watson) Brummitt | Convolvulaceae | 8 |
| Calystegia macrostegia | (Greene) Brummitt | Convolvulaceae | 8 |
| Calystegia sepium | (L.) R.Br. | Convolvulaceae | 8 |
| Camissonia strigulosa | (Fisch. & C.A.Mey.) P.H.Raven | Onagraceae | 8 |
| Camissoniopsis bistorta | (Nutt. ex Torr. & A.Gray) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camissoniopsis cheiranthifolia | (Hornem. ex Spreng.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camissoniopsis hirtella | (Greene) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camissoniopsis ignota | (Jeps.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camissoniopsis lewisii | (P.H.Raven) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camissoniopsis micrantha | (Hornem. ex Spreng.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camissoniopsis pallida | (Abrams) W.L.Wagner & Hoch | Onagraceae | 8 |
| Camonea umbellata | (L.) A.R.Simões & Staples | Convolvulaceae | 8 |
| Campyloneurum angustifolium | (Sw.) Fée | Polypodiaceae | 8 |
| Canavalia rosea | (Sw.) DC. | Fabaceae | 8 |
| Canavalia villosa | Benth. | Fabaceae | 8 |
| Canotia holacantha | Torr. | Celastraceae | 8 |
| Cantinoa mutabilis | (Rich.) Harley & J.F.B.Pastore | Lamiaceae | 8 |
| Capraria biflora | L. | Scrophulariaceae | 8 |
| Capraria frutescens | (Mill.) Briq. | Scrophulariaceae | 8 |
| Capsicum annuum | L. | Solanaceae | 8 |
| Cardamine breweri | S.Watson | Brassicaceae | 8 |
| Cardamine californica | (Nutt.) Greene | Brassicaceae | 8 |
| Cardamine oligosperma | Nutt. | Brassicaceae | 8 |
| Cardiospermum corindum | L. | Sapindaceae | 8 |
| Cardiospermum halicacabum | L. | Sapindaceae | 8 |
| Carex athrostachya | Olney | Cyperaceae | 8 |
| Carex capitata | Sol. | Cyperaceae | 8 |
| Carex douglasii | Boott | Cyperaceae | 8 |
| Carex fracta | Mack. | Cyperaceae | 8 |
| Carex globosa | Boott | Cyperaceae | 8 |
| Carex hendersonii | L.H.Bailey | Cyperaceae | 8 |
| Carex lasiocarpa | Ehrh. | Cyperaceae | 8 |
| Carex planostachys | Kunze | Cyperaceae | 8 |
| Carex praegracilis | W.Boott | Cyperaceae | 8 |
| Carex rossii | Boott | Cyperaceae | 8 |
| Carex senta | Boott | Cyperaceae | 8 |
| Carex spissa | L.H.Bailey ex Hemsl. | Cyperaceae | 8 |
| Carex subfusca | W.Boott | Cyperaceae | 8 |
| Carex triquetra | Boott | Cyperaceae | 8 |
| Carex vulpinoidea | Michx. | Cyperaceae | 8 |
| Carlowrightia arizonica | A.Gray | Acanthaceae | 8 |
| Carlowrightia linearifolia | (Torr.) A.Gray | Acanthaceae | 8 |
| Carlowrightia texana | Henrickson & T.F.Daniel | Acanthaceae | 8 |
| Carlowrightia torreyana | Wassh. | Acanthaceae | 8 |
| Carminatia tenuiflora | DC. | Asteraceae | 8 |
| Carnegiea gigantea | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Carphochaete bigelovii | A.Gray | Asteraceae | 8 |
| Cascabela ovata | (Cav.) Lippold | Apocynaceae | 8 |
| Cascabela thevetia | (L.) Lippold | Apocynaceae | 8 |
| Casearia arguta | Kunth | Salicaceae | 8 |
| Casearia corymbosa | Kunth | Salicaceae | 8 |
| Casearia sylvestris | Sw. | Salicaceae | 8 |
| Casearia tremula | (Griseb.) Griseb. ex C.Wright | Salicaceae | 8 |
| Casimiroa edulis | La Llave | Rutaceae | 8 |
| Castela emoryi | (A.Gray) Moran & Felger | Simaroubaceae | 8 |
| Castela peninsularis | Rose | Simaroubaceae | 8 |
| Castilla elastica | Cerv. | Moraceae | 8 |
| Castilleja affinis | Hook. & Arn. | Orobanchaceae | 8 |
| Castilleja arvensis | Schltdl. & Cham. | Orobanchaceae | 8 |
| Castilleja attenuata | (A.Gray) T.I.Chuang & Heckard | Orobanchaceae | 8 |
| Castilleja densiflora | (Benth.) T.I.Chuang & Heckard | Orobanchaceae | 8 |
| Castilleja exserta | (A.Heller) T.I.Chuang & Heckard | Orobanchaceae | 8 |
| Castilleja foliolosa | Hook. & Arn. | Orobanchaceae | 8 |
| Castilleja integra | A.Gray | Orobanchaceae | 8 |
| Castilleja lanata | A.Gray | Orobanchaceae | 8 |
| Castilleja martini | Abrams | Orobanchaceae | 8 |
| Castilleja miniata | Douglas ex Benth. | Orobanchaceae | 8 |
| Castilleja minor | (A.Gray) A.Gray | Orobanchaceae | 8 |
| Castilleja nelsonii | Eastw. | Orobanchaceae | 8 |
| Castilleja patriotica | Fernald | Orobanchaceae | 8 |
| Castilleja scorzonerifolia | Kunth | Orobanchaceae | 8 |
| Castilleja sessiliflora | Pursh | Orobanchaceae | 8 |
| Castilleja subinclusa | Greene | Orobanchaceae | 8 |
| Castilleja tenuiflora | Benth. | Orobanchaceae | 8 |
| Castilleja tenuifolia | M.Martens & Galeotti | Orobanchaceae | 8 |
| Cayaponia attenuata | (Hook. & Arn.) Cogn. | Cucurbitaceae | 8 |
| Ceanothus buxifolius | Willd. ex Schult. | Rhamnaceae | 8 |
| Ceanothus caeruleus | Lag. | Rhamnaceae | 8 |
| Ceanothus cordulatus | Kellogg | Rhamnaceae | 8 |
| Ceanothus crassifolius | Torr. | Rhamnaceae | 8 |
| Ceanothus cuneatus | (Hook.) Nutt. | Rhamnaceae | 8 |
| Ceanothus cyaneus | Eastw. | Rhamnaceae | 8 |
| Ceanothus fendleri | A.Gray | Rhamnaceae | 8 |
| Ceanothus leucodermis | Greene | Rhamnaceae | 8 |
| Ceanothus oliganthus | Nutt. | Rhamnaceae | 8 |
| Ceanothus palmeri | Trel. | Rhamnaceae | 8 |
| Ceanothus pauciflorus | DC. | Rhamnaceae | 8 |
| Ceanothus spinosus | Nutt. | Rhamnaceae | 8 |
| Ceanothus thyrsiflorus | Eschsch. | Rhamnaceae | 8 |
| Ceanothus tomentosus | Parry | Rhamnaceae | 8 |
| Ceanothus verrucosus | Nutt. | Rhamnaceae | 8 |
| Cecropia obtusifolia | Bertol. | Urticaceae | 8 |
| Cedrela odorata | L. | Meliaceae | 8 |
| Cedrela salvadorensis | Standl. | Meliaceae | 8 |
| Ceiba pentandra | (L.) Gaertn. | Malvaceae | 8 |
| Celosia floribunda | A.Gray | Amaranthaceae | 8 |
| Celosia nitida | Vahl | Amaranthaceae | 8 |
| Celtis caudata | Planch. | Cannabaceae | 8 |
| Celtis iguanaea | (Jacq.) Sarg. | Cannabaceae | 8 |
| Celtis laevigata | Willd. | Cannabaceae | 8 |
| Celtis pallida | Torr. | Cannabaceae | 8 |
| Celtis reticulata | Torr. | Cannabaceae | 8 |
| Cenchrus echinatus | L. | Poaceae | 8 |
| Cenchrus myosuroides | Kunth | Poaceae | 8 |
| Cenchrus palmeri | Vasey | Poaceae | 8 |
| Cenchrus spinifex | Cav. | Poaceae | 8 |
| Cenostigma eriostachys | (Benth.) Gagnon & G.P.Lewis | Fabaceae | 8 |
| Centromadia parryi | (Greene) Greene | Asteraceae | 8 |
| Centromadia perennis | Greene | Asteraceae | 8 |
| Centromadia pungens | Greene | Asteraceae | 8 |
| Centrosema virginianum | (L.) Benth. | Fabaceae | 8 |
| Cephalanthus occidentalis | L. | Rubiaceae | 8 |
| Cephalanthus salicifolius | Bonpl. | Rubiaceae | 8 |
| Cerastium brachypodum | (Engelm. ex A.Gray) B.L.Rob. | Caryophyllaceae | 8 |
| Cerastium nutans | Raf. | Caryophyllaceae | 8 |
| Ceratophyllum demersum | L. | Ceratophyllaceae | 8 |
| Cercocarpus betuloides | Nutt. | Rosaceae | 8 |
| Cercocarpus breviflorus | A.Gray | Rosaceae | 8 |
| Cercocarpus ledifolius | Nutt. | Rosaceae | 8 |
| Cercocarpus macrophyllus | C.K.Schneid. | Rosaceae | 8 |
| Cercocarpus montanus | Raf. | Rosaceae | 8 |
| Cestrum diurnum | L. | Solanaceae | 8 |
| Cestrum nocturnum | L. | Solanaceae | 8 |
| Cestrum tomentosum | L.f. | Solanaceae | 8 |
| Cevallia sinuata | Lag. | Loasaceae | 8 |
| Chaenactis artemisiifolia | A.Gray | Asteraceae | 8 |
| Chaenactis carphoclinia | A.Gray | Asteraceae | 8 |
| Chaenactis fremontii | A.Gray | Asteraceae | 8 |
| Chaenactis glabriuscula | DC. | Asteraceae | 8 |
| Chaenactis lacera | Greene | Asteraceae | 8 |
| Chaenactis parishii | A.Gray | Asteraceae | 8 |
| Chaenactis stevioides | Hook. & Arn. | Asteraceae | 8 |
| Chaenactis xantiana | A.Gray | Asteraceae | 8 |
| Chaetopappa ericoides | (Torr.) G.L.Nesom | Asteraceae | 8 |
| Chamaebatia australis | (Brandegee) Abrams | Rosaceae | 8 |
| Chamaecrista absus | (L.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Chamaecrista nictitans | (L.) Moench | Fabaceae | 8 |
| Chamaecrista rotundifolia | (Pers.) Greene | Fabaceae | 8 |
| Chamaesaracha coniodes | (Moric. ex Dunal) Benth. & Hook.f. ex B.D.Jacks. | Solanaceae | 8 |
| Chamaesaracha coronopus | (Dunal) A.Gray | Solanaceae | 8 |
| Chamissoa altissima | Kunth | Amaranthaceae | 8 |
| Chaptalia nutans | (L.) Pol. | Asteraceae | 8 |
| Chaptalia texana | Greene | Asteraceae | 8 |
| Cheilanthes leucopoda | Link | Pteridaceae | 8 |
| Chenopodium atrovirens | Rydb. | Chenopodiaceae | 8 |
| Chenopodium berlandieri | Moq. | Chenopodiaceae | 8 |
| Chenopodium fremontii | S.Watson | Chenopodiaceae | 8 |
| Chenopodium incanum | (S.Watson) A.Heller | Chenopodiaceae | 8 |
| Chenopodium leptophyllum | (Nutt. ex Moq.) B.D.Jacks. | Chenopodiaceae | 8 |
| Chilopsis linearis | (Cav.) Sweet | Bignoniaceae | 8 |
| Chimaphila maculata | (L.) Pursh | Ericaceae | 8 |
| Chimaphila menziesii | (R.Br. ex D.Don) Spreng. | Ericaceae | 8 |
| Chimaphila umbellata | (L.) W.P.C.Barton | Ericaceae | 8 |
| Chiococca alba | (L.) Hitchc. | Rubiaceae | 8 |
| Chloracantha spinosa | (Benth.) G.L.Nesom | Asteraceae | 8 |
| Chloracantha spinosissima | (Brandegee) G.L.Nesom | Asteraceae | 8 |
| Chloris virgata | Sw. | Poaceae | 8 |
| Chloroleucon mangense | (Jacq.) Britton & Rose | Fabaceae | 8 |
| Chloropyron maritimum | (Nutt. ex Benth.) A.Heller | Orobanchaceae | 8 |
| Choisya dumosa | (Torr. & A.Gray) A.Gray | Rutaceae | 8 |
| Chorizanthe brevicornu | Torr. | Polygonaceae | 8 |
| Chorizanthe corrugata | (Torr.) Torr. & A.Gray | Polygonaceae | 8 |
| Chorizanthe fimbriata | Nutt. | Polygonaceae | 8 |
| Chorizanthe leptotheca | Goodman | Polygonaceae | 8 |
| Chorizanthe procumbens | Nutt. | Polygonaceae | 8 |
| Chorizanthe rigida | (Torr.) Torr. & A.Gray | Polygonaceae | 8 |
| Chromolaena collina | (DC.) R.M.King & H.Rob. | Asteraceae | 8 |
| Chromolaena odorata | (L.) R.M.King & H.Rob. | Asteraceae | 8 |
| Chromolaena pulchella | (Kunth) R.M.King & H.Rob. | Asteraceae | 8 |
| Chromolaena sagittata | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Chthamalia parviflora | (Torr.) L.O.Alvarado & E.B.Cortez | Apocynaceae | 8 |
| Chthamalia producta | (Torr.) L.O.Alvarado & E.B.Cortez | Apocynaceae | 8 |
| Chylismia cardiophylla | (Torr.) Small | Onagraceae | 8 |
| Chylismia claviformis | (Torr. & Frém.) A.Heller | Onagraceae | 8 |
| Cicuta maculata | L. | Apiaceae | 8 |
| Cipura campanulata | Ravenna | Iridaceae | 8 |
| Cirsium arizonicum | (A.Gray) Petr. | Asteraceae | 8 |
| Cirsium ehrenbergii | Sch.Bip. | Asteraceae | 8 |
| Cirsium mexicanum | DC. | Asteraceae | 8 |
| Cirsium mohavense | (Greene) Petr. | Asteraceae | 8 |
| Cirsium neomexicanum | A.Gray | Asteraceae | 8 |
| Cirsium occidentale | (Nutt.) Jeps. | Asteraceae | 8 |
| Cirsium rhaphilepis | Petr. | Asteraceae | 8 |
| Cirsium scariosum | Nutt. | Asteraceae | 8 |
| Cirsium wheeleri | Petr. | Asteraceae | 8 |
| Cissampelos pareira | L. | Menispermaceae | 8 |
| Cissus alata | Jacq. | Vitaceae | 8 |
| Cissus erosa | Rich. | Vitaceae | 8 |
| Cissus microcarpa | Vahl | Vitaceae | 8 |
| Cissus tiliacea | Kunth | Vitaceae | 8 |
| Cissus trifoliata | (L.) L. | Vitaceae | 8 |
| Cissus verticillata | (L.) Nicolson & C.E.Jarvis | Vitaceae | 8 |
| Cistanthe maritima | (Nutt.) Carolin ex M.A.Hershkovitz | Montiaceae | 8 |
| Cistanthe monandra | (Nutt.) Hershk. | Montiaceae | 8 |
| Cistanthe monosperma | (Greene) Hershk. | Montiaceae | 8 |
| Cistanthe umbellata | (Torr.) Hershk. | Montiaceae | 8 |
| Citharexylum berlandieri | B.L.Rob. | Verbenaceae | 8 |
| Citharexylum flabellifolium | S.Watson | Verbenaceae | 8 |
| Cladium mariscus | (L.) Pohl | Cyperaceae | 8 |
| Clarkia delicata | (Abrams) A.Nelson & J.F.Macbr. | Onagraceae | 8 |
| Clarkia epilobioides | (Nutt.) A.Nelson & J.F.Macbr. | Onagraceae | 8 |
| Clarkia purpurea | (Curtis) A.Nelson & J.F.Macbr. | Onagraceae | 8 |
| Clarkia rhomboidea | Douglas | Onagraceae | 8 |
| Clarkia similis | F.H.Lewis & W.R.Ernst | Onagraceae | 8 |
| Clarkia unguiculata | Lindl. | Onagraceae | 8 |
| Claytonia exigua | Torr. & A.Gray | Montiaceae | 8 |
| Claytonia parviflora | Douglas | Montiaceae | 8 |
| Claytonia perfoliata | Donn ex Willd. | Montiaceae | 8 |
| Clematis dioica | L. | Ranunculaceae | 8 |
| Clematis drummondii | Torr. & A.Gray | Ranunculaceae | 8 |
| Clematis lasiantha | Nutt. | Ranunculaceae | 8 |
| Clematis ligusticifolia | Nutt. | Ranunculaceae | 8 |
| Clematis pauciflora | Nutt. ex Torr. & A.Gray | Ranunculaceae | 8 |
| Clematis pitcheri | Torr. & A.Gray | Ranunculaceae | 8 |
| Cleome dodecandra | L. | Cleomaceae | 8 |
| Cleome uniglandulosa | Cav. | Cleomaceae | 8 |
| Cleomella arborea | (Nutt.) Roalson & J.C.Hall | Cleomaceae | 8 |
| Cleomella lutea | (Hook.) Roalson & J.C.Hall | Cleomaceae | 8 |
| Cleomella multicaulis | (DC.) J.C.Hall & Roalson | Cleomaceae | 8 |
| Cleomella palmeri | (A.Gray) J.C.Hall & Roalson | Cleomaceae | 8 |
| Cleomella refracta | (Engelm.) J.C.Hall & Roalson | Cleomaceae | 8 |
| Clethra mexicana | DC. | Clethraceae | 8 |
| Clethra rosei | Britton | Clethraceae | 8 |
| Clinopodium brownei | (Sw.) Kuntze | Lamiaceae | 8 |
| Clinopodium chandleri | (Brandegee) P.D.Cantino & Wagstaff | Lamiaceae | 8 |
| Clinopodium macrostemum | (Moc. & Sessé ex Benth.) Kuntze | Lamiaceae | 8 |
| Clitoria mariana | L. | Fabaceae | 8 |
| Clusia salvinii | Donn.Sm. | Clusiaceae | 8 |
| Cneoridium dumosum | Hook.f. | Rutaceae | 8 |
| Cnidoscolus angustidens | Torr. | Euphorbiaceae | 8 |
| Cnidoscolus maculatus | (Brandegee) Pax & K.Hoffm. | Euphorbiaceae | 8 |
| Cnidoscolus tepiquensis | (Costantin & Gallaud) Lundell | Euphorbiaceae | 8 |
| Coccocypselum hirsutum | Bartl. ex DC. | Rubiaceae | 8 |
| Coccoloba uvifera | (L.) L. | Polygonaceae | 8 |
| Cochemiea dioica | (K.Brandegee) Doweld | Cactaceae | 8 |
| Cochemiea grahamii | (Engelm.) Doweld | Cactaceae | 8 |
| Cochemiea mazatlanensis | (K.Schum.) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Cochemiea phitauiana | (E.M.Baxter) Doweld | Cactaceae | 8 |
| Cochemiea poselgeri | (Hildm.) Britton & Rose | Cactaceae | 8 |
| Cochemiea sheldonii | (Britton & Rose) Doweld | Cactaceae | 8 |
| Cochliasanthus caracalla | (L.) Trew | Fabaceae | 8 |
| Cochlospermum vitifolium | (Willd.) Spreng. | Bixaceae | 8 |
| Cojoba arborea | (L.) Britton & Rose | Fabaceae | 8 |
| Collinsia childii | Parry ex A.Gray | Plantaginaceae | 8 |
| Collinsia concolor | Greene | Plantaginaceae | 8 |
| Cologania angustifolia | Kunth | Fabaceae | 8 |
| Cologania broussonetii | (Balb.) DC. | Fabaceae | 8 |
| Cologania obovata | Schltdl. | Fabaceae | 8 |
| Cologania procumbens | Kunth | Fabaceae | 8 |
| Colubrina californica | I.M.Johnst. | Rhamnaceae | 8 |
| Colubrina triflora | Brongn. | Rhamnaceae | 8 |
| Colubrina viridis | (M.E.Jones) M.C.Johnst. | Rhamnaceae | 8 |
| Comandra umbellata | (L.) Nutt. | Santalaceae | 8 |
| Comarostaphylis diversifolia | (Parry) Greene | Ericaceae | 8 |
| Comarostaphylis glaucescens | (Kunth) Zucc. ex Klotzsch | Ericaceae | 8 |
| Comarostaphylis polifolia | (Kunth) Zucc. ex Klotzsch | Ericaceae | 8 |
| Combretum farinosum | Kunth | Combretaceae | 8 |
| Combretum fruticosum | (Loefl.) Stuntz | Combretaceae | 8 |
| Commelina dianthifolia | Redouté | Commelinaceae | 8 |
| Commelina erecta | L. | Commelinaceae | 8 |
| Commelina tuberosa | L. | Commelinaceae | 8 |
| Comocladia macrophylla | (Hook. & Arn.) L.Riley | Anacardiaceae | 8 |
| Condalia correllii | M.C.Johnst. | Rhamnaceae | 8 |
| Condalia globosa | I.M.Johnst. | Rhamnaceae | 8 |
| Condalia spathulata | A.Gray | Rhamnaceae | 8 |
| Condalia velutina | I.M.Johnst. | Rhamnaceae | 8 |
| Condalia warnockii | M.C.Johnst. | Rhamnaceae | 8 |
| Condea albida | (Kunth) Harley & J.F.B.Pastore | Lamiaceae | 8 |
| Condea emoryi | (Torr.) Harley & J.F.B.Pastore | Lamiaceae | 8 |
| Condea laniflora | (Benth.) Harley & J.F.B.Pastore | Lamiaceae | 8 |
| Conocarpus erectus | L. | Combretaceae | 8 |
| Conoclinium betonicifolium | (Mill.) R.M.King & H.Rob. | Asteraceae | 8 |
| Conoclinium greggii | Small | Asteraceae | 8 |
| Conopholis alpina | Liebm. | Orobanchaceae | 8 |
| Convolvulus equitans | Benth. | Convolvulaceae | 8 |
| Convolvulus simulans | L.M.Perry | Convolvulaceae | 8 |
| Conyza laevigata | (Rich.) Pruski | Asteraceae | 8 |
| Conzattia multiflora | (B.L.Rob.) Standl. | Fabaceae | 8 |
| Conzattia sericea | Standl. | Fabaceae | 8 |
| Corallorhiza odontorhiza | (Willd.) Nutt. | Orchidaceae | 8 |
| Corchorus aestuans | L. | Malvaceae | 8 |
| Corchorus siliquosus | L. | Malvaceae | 8 |
| Cordia alliodora | (Ruiz & Pav.) Oken | Cordiaceae | 8 |
| Cordia dentata | Poir. | Cordiaceae | 8 |
| Cordia elaeagnoides | A.DC. | Cordiaceae | 8 |
| Cordia parvifolia | A.DC. | Cordiaceae | 8 |
| Cordylanthus nevinii | A.Gray | Orobanchaceae | 8 |
| Cordylanthus rigidus | (Benth.) Jeps. | Orobanchaceae | 8 |
| Cordylanthus wrightii | A.Gray | Orobanchaceae | 8 |
| Coreocarpus arizonicus | S.F.Blake | Asteraceae | 8 |
| Coreopsis californica | (Nutt.) H.Sharsm. | Asteraceae | 8 |
| Coreopsis gigantea | (Kellogg) H.M.Hall | Asteraceae | 8 |
| Coreopsis maritima | Hook.f. | Asteraceae | 8 |
| Corethrogyne filaginifolia | (Hook. & Arn.) Nutt. | Asteraceae | 8 |
| Coriaria ruscifolia | L. | Coriariaceae | 8 |
| Cornus disciflora | Moc. & Sessé ex DC. | Cornaceae | 8 |
| Cornus excelsa | Kunth | Cornaceae | 8 |
| Cornus sericea | L. | Cornaceae | 8 |
| Corydalis aurea | Willd. | Papaveraceae | 8 |
| Coryphantha compacta | (Engelm.) Orcutt | Cactaceae | 8 |
| Coryphantha robustispina | (Schott ex Engelm.) Britton & Rose | Cactaceae | 8 |
| Cosmos bipinnatus | Cav. | Asteraceae | 8 |
| Cosmos caudatus | Kunth | Asteraceae | 8 |
| Cosmos crithmifolius | Kunth | Asteraceae | 8 |
| Cosmos scabiosoides | Kunth | Asteraceae | 8 |
| Cosmos sulphureus | Cav. | Asteraceae | 8 |
| Costus pictus | D.Don | Costaceae | 8 |
| Cottea pappophoroides | Kunth | Poaceae | 8 |
| Cottsia californica | (Benth.) W.R.Anderson & C.Davis | Malpighiaceae | 8 |
| Cottsia gracilis | (A.Gray) W.R.Anderson & C.Davis | Malpighiaceae | 8 |
| Couepia polyandra | (Kunth) Rose | Chrysobalanaceae | 8 |
| Coulterella capitata | Vasey & Rose | Asteraceae | 8 |
| Coulteria platyloba | (S.Watson) N.Zamora | Fabaceae | 8 |
| Coursetia caribaea | (Jacq.) Lavin | Fabaceae | 8 |
| Coursetia glandulosa | A.Gray | Fabaceae | 8 |
| Crassula aquatica | (L.) Schönland | Crassulaceae | 8 |
| Crassula connata | A.Berger | Crassulaceae | 8 |
| Crataegus mexicana | Moc. & Sessé ex DC. | Rosaceae | 8 |
| Crateva tapia | L. | Capparaceae | 8 |
| Crescentia alata | Kunth | Bignoniaceae | 8 |
| Crescentia cujete | L. | Bignoniaceae | 8 |
| Cressa truxillensis | Kunth | Convolvulaceae | 8 |
| Critonia morifolia | (Mill.) R.M.King & H.Rob. | Asteraceae | 8 |
| Critonia quadrangularis | (DC.) R.M.King & H.Rob. | Asteraceae | 8 |
| Crocanthemum aldersonii | (Greene) Janch. | Cistaceae | 8 |
| Crocanthemum canadense | (L.) Britton | Cistaceae | 8 |
| Crocanthemum glomeratum | (Lag.) Janch. | Cistaceae | 8 |
| Crocanthemum scoparium | (Nutt.) Millsp. | Cistaceae | 8 |
| Crossosoma bigelovii | S.Watson | Crossosomataceae | 8 |
| Crossosoma californicum | Nutt. | Crossosomataceae | 8 |
| Crotalaria cajanifolia | Kunth | Fabaceae | 8 |
| Crotalaria incana | L. | Fabaceae | 8 |
| Crotalaria micans | Link | Fabaceae | 8 |
| Crotalaria mollicula | Kunth | Fabaceae | 8 |
| Crotalaria pumila | Ortega | Fabaceae | 8 |
| Crotalaria purshii | DC. | Fabaceae | 8 |
| Crotalaria rotundifolia | J.F.Gmel. | Fabaceae | 8 |
| Crotalaria sagittalis | L. | Fabaceae | 8 |
| Croton adspersus | Benth. | Euphorbiaceae | 8 |
| Croton californicus | Müll.Arg. | Euphorbiaceae | 8 |
| Croton ciliatoglandulifer | Ortega | Euphorbiaceae | 8 |
| Croton cortesianus | Kunth | Euphorbiaceae | 8 |
| Croton dioicus | Cav. | Euphorbiaceae | 8 |
| Croton draco | Schltdl. | Euphorbiaceae | 8 |
| Croton fruticulosus | Torr. | Euphorbiaceae | 8 |
| Croton glandulosus | L. | Euphorbiaceae | 8 |
| Croton hirtus | L'Hér. | Euphorbiaceae | 8 |
| Croton humilis | L. | Euphorbiaceae | 8 |
| Croton leucophyllus | Müll.Arg. | Euphorbiaceae | 8 |
| Croton lindquistii | V.W.Steinm. | Euphorbiaceae | 8 |
| Croton magdalenae | Millsp. | Euphorbiaceae | 8 |
| Croton pottsii | (Klotzsch) Müll.Arg. | Euphorbiaceae | 8 |
| Croton punctatus | Jacq. | Euphorbiaceae | 8 |
| Croton sonorae | Torr. | Euphorbiaceae | 8 |
| Croton texensis | (Klotzsch) Müll.Arg. | Euphorbiaceae | 8 |
| Croton wigginsii | L.C.Wheeler | Euphorbiaceae | 8 |
| Crusea coccinea | DC. | Rubiaceae | 8 |
| Crusea hispida | (Mill.) B.L.Rob. | Rubiaceae | 8 |
| Crusea longiflora | (Roem. & Schult.) W.R.Anderson | Rubiaceae | 8 |
| Crusea simplex | (Willd.) J.H.Kirkbr. & Wiersema | Rubiaceae | 8 |
| Cryptantha barbigera | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha crassisepala | (Torr. & A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha intermedia | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha maritima | (Greene) Greene | Boraginaceae | 8 |
| Cryptantha micromeres | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha microstachys | Greene | Boraginaceae | 8 |
| Cryptantha pterocarya | (Torr.) Greene | Boraginaceae | 8 |
| Cryptantha utahensis | (A.Gray) Greene | Boraginaceae | 8 |
| Ctenodon niveus | (Brandegee) A.Delgado | Fabaceae | 8 |
| Cucurbita argyrosperma | C.Huber | Cucurbitaceae | 8 |
| Cucurbita digitata | A.Gray | Cucurbitaceae | 8 |
| Cucurbita foetidissima | Kunth | Cucurbitaceae | 8 |
| Cucurbita palmata | S.Watson | Cucurbitaceae | 8 |
| Cucurbita pepo | L. | Cucurbitaceae | 8 |
| Cupania dentata | Moc. & Sessé | Sapindaceae | 8 |
| Cupania glabra | Sw. | Sapindaceae | 8 |
| Cuphea aequipetala | Cav. | Lythraceae | 8 |
| Cuphea appendiculata | Benth. | Lythraceae | 8 |
| Cuphea avigera | B.L.Rob. & Seaton | Lythraceae | 8 |
| Cuphea hookeriana | Walp. | Lythraceae | 8 |
| Cuphea hyssopifolia | Kunth | Lythraceae | 8 |
| Cuphea jorullensis | Kunth | Lythraceae | 8 |
| Cuphea leptopoda | Hemsl. | Lythraceae | 8 |
| Cuphea llavea | Lex. | Lythraceae | 8 |
| Cuphea procumbens | Ortega | Lythraceae | 8 |
| Cuphea viscosissima | Jacq. | Lythraceae | 8 |
| Cuphea wrightii | A.Gray | Lythraceae | 8 |
| Curatella americana | L. | Dilleniaceae | 8 |
| Cuscuta californica | Hook. & Arn. | Convolvulaceae | 8 |
| Cuscuta campestris | Yunck. | Convolvulaceae | 8 |
| Cuscuta denticulata | Engelm. | Convolvulaceae | 8 |
| Cuscuta pacifica | Costea & M.A.R.Wright | Convolvulaceae | 8 |
| Cuscuta subinclusa | Durand & Hilg. | Convolvulaceae | 8 |
| Cuscuta tuberculata | Brandegee | Convolvulaceae | 8 |
| Cuscuta umbellata | Kunth | Convolvulaceae | 8 |
| Cyclanthera carthagenensis | (Jacq.) H.Schaef. & S.S.Renner | Cucurbitaceae | 8 |
| Cylindropuntia acanthocarpa | (Engelm. & J.M.Bigelow) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia alcahes | (F.A.C.Weber) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia arbuscula | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia bigelovii | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia californica | (Torr. & A.Gray) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia cholla | (F.A.C.Weber) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia echinocarpa | (Engelm. & J.M.Bigelow) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia fulgida | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia ganderi | (C.B.Wolf) Rebman & Pinkava | Cactaceae | 8 |
| Cylindropuntia imbricata | (Haw.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia kleiniae | (DC.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia leptocaulis | (DC.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia molesta | (K.Brandegee) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia munzii | (C.B.Wolf) Backeb. | Cactaceae | 8 |
| Cylindropuntia prolifera | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia ramosissima | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia tesajo | (Engelm. ex J.M.Coult.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia thurberi | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia wolfii | (L.D.Benson) M.A.Baker | Cactaceae | 8 |
| Cymopterus lemmonii | (J.M.Coult. & Rose) Dorn | Apiaceae | 8 |
| Cyperus aggregatus | (Willd.) Endl. | Cyperaceae | 8 |
| Cyperus articulatus | L. | Cyperaceae | 8 |
| Cyperus brevifolius | (Rottb.) Hassk. | Cyperaceae | 8 |
| Cyperus compressus | L. | Cyperaceae | 8 |
| Cyperus cuspidatus | Kunth | Cyperaceae | 8 |
| Cyperus entrerianus | Boeckeler | Cyperaceae | 8 |
| Cyperus eragrostis | Lam. | Cyperaceae | 8 |
| Cyperus esculentus | L. | Cyperaceae | 8 |
| Cyperus fendlerianus | Boeckeler | Cyperaceae | 8 |
| Cyperus flavescens | L. | Cyperaceae | 8 |
| Cyperus hermaphroditus | (Jacq.) Standl. | Cyperaceae | 8 |
| Cyperus laevigatus | L. | Cyperaceae | 8 |
| Cyperus lanceolatus | Poir. | Cyperaceae | 8 |
| Cyperus ligularis | L. | Cyperaceae | 8 |
| Cyperus manimae | Kunth | Cyperaceae | 8 |
| Cyperus melanostachyus | Kunth | Cyperaceae | 8 |
| Cyperus ochraceus | Vahl | Cyperaceae | 8 |
| Cyperus odoratus | L. | Cyperaceae | 8 |
| Cyperus oxylepis | Nees ex Steud. | Cyperaceae | 8 |
| Cyperus polystachyos | Rottb. | Cyperaceae | 8 |
| Cyperus retroflexus | Buckley | Cyperaceae | 8 |
| Cyperus seslerioides | Kunth | Cyperaceae | 8 |
| Cyperus sesquiflorus | (Torr.) Mattf. & Kük. | Cyperaceae | 8 |
| Cyperus sphaerolepis | Boeckeler | Cyperaceae | 8 |
| Cyperus squarrosus | L. | Cyperaceae | 8 |
| Cyperus strigosus | L. | Cyperaceae | 8 |
| Cyperus subsquarrosus | (Muhl.) Bauters | Cyperaceae | 8 |
| Cyperus surinamensis | Rottb. | Cyperaceae | 8 |
| Cyphomeris gypsophiloides | (M.Martens & Galeotti) Standl. | Nyctaginaceae | 8 |
| Cyrtocarpa edulis | (Brandegee) Standl. | Anacardiaceae | 8 |
| Cyrtopodium macrobulbon | (Lex.) G.A.Romero & Carnevali | Orchidaceae | 8 |
| Cystopteris fragilis | (L.) Bernh. | Cystopteridaceae | 8 |
| Cystopteris reevesiana | Lellinger | Cystopteridaceae | 8 |
| Dahlia coccinea | Cav. | Asteraceae | 8 |
| Dahlia sherffii | P.D.Sørensen | Asteraceae | 8 |
| Dahlia sorensenii | H.V.Hansen & Hjert. | Asteraceae | 8 |
| Dalea albiflora | A.Gray | Fabaceae | 8 |
| Dalea bicolor | Humb. & Bonpl. ex Willd. | Fabaceae | 8 |
| Dalea candida | Willd. | Fabaceae | 8 |
| Dalea formosa | Torr. | Fabaceae | 8 |
| Dalea greggii | A.Gray | Fabaceae | 8 |
| Dalea leporina | (Aiton) Bullock | Fabaceae | 8 |
| Dalea mollis | Benth. | Fabaceae | 8 |
| Dalea mollissima | (Rydb.) Munz | Fabaceae | 8 |
| Dalea neomexicana | (A.Gray) Cory | Fabaceae | 8 |
| Dalea pogonathera | A.Gray | Fabaceae | 8 |
| Dalea polygonoides | A.Gray | Fabaceae | 8 |
| Dalea pringlei | A.Gray | Fabaceae | 8 |
| Dalea pulchra | Gentry | Fabaceae | 8 |
| Dalea rubescens | S.Watson | Fabaceae | 8 |
| Dalea urceolata | Greene | Fabaceae | 8 |
| Dalea versicolor | Zucc. | Fabaceae | 8 |
| Dalea wrightii | A.Gray | Fabaceae | 8 |
| Dalechampia scandens | L. | Euphorbiaceae | 8 |
| Damburneya salicifolia | (Kunth) Trofimov & Rohwer | Lauraceae | 8 |
| Dasylirion wheeleri | S.Watson ex Rothr. | Asparagaceae | 8 |
| Datisca glomerata | (C.Presl) Baill. | Datiscaceae | 8 |
| Datura discolor | Bernh. | Solanaceae | 8 |
| Datura innoxia | Mill. | Solanaceae | 8 |
| Datura quercifolia | Kunth | Solanaceae | 8 |
| Datura stramonium | L. | Solanaceae | 8 |
| Datura wrightii | Regel | Solanaceae | 8 |
| Daucus pusillus | Michx. | Apiaceae | 8 |
| Deinandra conjugens | (D.D.Keck) B.G.Baldwin | Asteraceae | 8 |
| Deinandra fasciculata | (DC.) Greene | Asteraceae | 8 |
| Deinandra floribunda | Davidson & Moxley | Asteraceae | 8 |
| Deinandra kelloggii | Greene | Asteraceae | 8 |
| Deinandra paniculata | Davidson & Moxley | Asteraceae | 8 |
| Delilia biflora | Kuntze | Asteraceae | 8 |
| Delphinium cardinale | Hook. | Ranunculaceae | 8 |
| Delphinium parishii | A.Gray | Ranunculaceae | 8 |
| Delphinium parryi | A.Gray | Ranunculaceae | 8 |
| Delphinium patens | Benth. | Ranunculaceae | 8 |
| Delphinium scaposum | Greene | Ranunculaceae | 8 |
| Delphinium scopulorum | A.Gray | Ranunculaceae | 8 |
| Delphinium wootonii | Rydb. | Ranunculaceae | 8 |
| Dendromecon rigida | Benth. | Papaveraceae | 8 |
| Deschampsia danthonioides | (Trin.) Benth. | Poaceae | 8 |
| Deschampsia elongata | (Hook.) Munro | Poaceae | 8 |
| Descurainia incisa | (Engelm.) Britton | Brassicaceae | 8 |
| Descurainia pinnata | (Walter) Britton | Brassicaceae | 8 |
| Desmanthus bicornutus | S.Watson | Fabaceae | 8 |
| Desmanthus cooleyi | (Eaton) Trel. ex Branner & Coville | Fabaceae | 8 |
| Desmanthus fruticosus | Rose | Fabaceae | 8 |
| Desmanthus virgatus | (L.) Willd. | Fabaceae | 8 |
| Desmodium batocaulon | A.Gray | Fabaceae | 8 |
| Desmodium canescens | (L.) DC. | Fabaceae | 8 |
| Desmodium grahamii | A.Gray | Fabaceae | 8 |
| Desmodium incanum | (Sw.) DC. | Fabaceae | 8 |
| Desmodium infractum | DC. | Fabaceae | 8 |
| Desmodium intortum | (Mill.) Urb. | Fabaceae | 8 |
| Desmodium macrostachyum | Hemsl. | Fabaceae | 8 |
| Desmodium molliculum | (Kunth) DC. | Fabaceae | 8 |
| Desmodium orbiculare | Schltdl. | Fabaceae | 8 |
| Desmodium procumbens | (Mill.) C.L.Hitchc. | Fabaceae | 8 |
| Desmodium rosei | B.G.Schub. | Fabaceae | 8 |
| Desmodium scorpiurus | (Sw.) Poir. | Fabaceae | 8 |
| Desmodium tortuosum | (Sw.) DC. | Fabaceae | 8 |
| Desmodium uncinatum | (Jacq.) DC. | Fabaceae | 8 |
| Dianthera candicans | (Nees) Benth. & Hook.f. ex Hemsl. | Acanthaceae | 8 |
| Diaperia verna | (Raf.) Morefield | Asteraceae | 8 |
| Diastatea tenera | (A.Gray) McVaugh | Campanulaceae | 8 |
| Dichanthelium oligosanthes | (Schult.) Gould | Poaceae | 8 |
| Dichelostemma capitatum | (Benth.) Alph.Wood | Asparagaceae | 8 |
| Dichondra occidentalis | House | Convolvulaceae | 8 |
| Dichondra sericea | Sw. | Convolvulaceae | 8 |
| Dichromanthus aurantiacus | (La Llave & Lex.) Salazar & Soto Arenas | Orchidaceae | 8 |
| Dichromanthus cinnabarinus | (La Llave & Lex.) Garay | Orchidaceae | 8 |
| Dichromanthus michuacanus | (La Llave & Lex.) Salazar & Soto Arenas | Orchidaceae | 8 |
| Dicliptera resupinata | (Vahl) Juss. | Acanthaceae | 8 |
| Dicoria canescens | A.Gray | Asteraceae | 8 |
| Dicranostegia orcuttiana | (A.Gray) Pennell | Orobanchaceae | 8 |
| Dictyanthus pavonii | Decne. | Apocynaceae | 8 |
| Dictyanthus reticulatus | (Turcz.) Benth. & Hook.f. ex Hemsl. | Apocynaceae | 8 |
| Dictyanthus sepicola | (W.D.Stevens) W.D.Stevens | Apocynaceae | 8 |
| Dieteria asteroides | Torr. | Asteraceae | 8 |
| Dieteria canescens | (Pursh) Nutt. | Asteraceae | 8 |
| Digitacalia jatrophoides | (Kunth) Pippen | Asteraceae | 8 |
| Digitaria californica | (Benth.) Henrard | Poaceae | 8 |
| Digitaria filiformis | (L.) Koeler | Poaceae | 8 |
| Digitaria insularis | (L.) Mez ex Ekman | Poaceae | 8 |
| Diospyros intricata | (A.Gray) Standl. | Ebenaceae | 8 |
| Diospyros rosei | Standl. | Ebenaceae | 8 |
| Diphysa suberosa | S.Watson | Fabaceae | 8 |
| Diplachne fusca | (L.) P.Beauv. | Poaceae | 8 |
| Diplacus bigelovii | (A.Gray) G.L.Nesom | Phrymaceae | 8 |
| Diplacus brevipes | (Benth.) G.L.Nesom | Phrymaceae | 8 |
| Diplacus clevelandii | (Brandegee) Greene | Phrymaceae | 8 |
| Diplacus fremontii | (Benth.) G.L.Nesom | Phrymaceae | 8 |
| Diplacus longiflorus | Nutt. | Phrymaceae | 8 |
| Diplacus puniceus | Nutt. | Phrymaceae | 8 |
| Disakisperma dubium | (Kunth) P.M.Peterson & N.Snow | Poaceae | 8 |
| Distichlis littoralis | (Engelm.) H.L.Bell & Columbus | Poaceae | 8 |
| Distichlis spicata | (L.) Greene | Poaceae | 8 |
| Distimake aegyptius | (L.) A.R.Simões & Staples | Convolvulaceae | 8 |
| Distimake aureus | (Kellogg) A.R.Simões & Staples | Convolvulaceae | 8 |
| Distimake cissoides | (Lam.) A.R.Simões & Staples | Convolvulaceae | 8 |
| Distimake dissectus | (Jacq.) A.R.Simões & Staples | Convolvulaceae | 8 |
| Distimake quinquefolius | (L.) A.R.Simões & Staples | Convolvulaceae | 8 |
| Ditaxis brandegeei | (Millsp.) Rose & Standl. | Euphorbiaceae | 8 |
| Ditaxis lanceolata | (Benth.) Pax & K.Hoffm. | Euphorbiaceae | 8 |
| Ditaxis serrata | (Torr.) A.Heller | Euphorbiaceae | 8 |
| Dithyrea californica | Harv. | Brassicaceae | 8 |
| Dithyrea maritima | (Davidson) Davidson | Brassicaceae | 8 |
| Dodonaea viscosa | Jacq. | Sapindaceae | 8 |
| Dolichandra unguis-cati | (L.) L.G.Lohmann | Bignoniaceae | 8 |
| Dorstenia contrajerva | L. | Moraceae | 8 |
| Dorstenia drakena | L. | Moraceae | 8 |
| Downingia cuspidata | (Greene) Rattan | Campanulaceae | 8 |
| Draba helleriana | Greene | Brassicaceae | 8 |
| Dracocephalum parviflorum | Nutt. | Lamiaceae | 8 |
| Drymaria debilis | Brandegee | Caryophyllaceae | 8 |
| Drymaria glandulosa | Bartl. | Caryophyllaceae | 8 |
| Drymaria holosteoides | Benth. | Caryophyllaceae | 8 |
| Drymaria leptophylla | (Cham. & Schltdl.) Fenzl ex Rohrb. | Caryophyllaceae | 8 |
| Drymaria molluginea | (Ser.) Didr. | Caryophyllaceae | 8 |
| Drymaria villosa | Cham. & Schltdl. | Caryophyllaceae | 8 |
| Drymocallis glandulosa | (Lindl.) Rydb. | Rosaceae | 8 |
| Dryopetalon palmeri | O.E.Schulz | Brassicaceae | 8 |
| Dryopetalon runcinatum | A.Gray | Brassicaceae | 8 |
| Drypetes lateriflora | (Sw.) Krug & Urb. | Putranjivaceae | 8 |
| Dudleya abramsii | Rose | Crassulaceae | 8 |
| Dudleya anthonyi | Rose | Crassulaceae | 8 |
| Dudleya arizonica | Rose | Crassulaceae | 8 |
| Dudleya attenuata | (S.Watson) Moran | Crassulaceae | 8 |
| Dudleya cultrata | Rose | Crassulaceae | 8 |
| Dudleya edulis | (Nutt.) Moran | Crassulaceae | 8 |
| Dudleya ingens | Rose | Crassulaceae | 8 |
| Dudleya lanceolata | (Nutt.) Britton & Rose | Crassulaceae | 8 |
| Dudleya pulverulenta | (Nutt.) Britton & Rose | Crassulaceae | 8 |
| Dudleya saxosa | (M.E.Jones) Britton & Rose | Crassulaceae | 8 |
| Dudleya variegata | (S.Watson) Moran | Crassulaceae | 8 |
| Duranta erecta | L. | Verbenaceae | 8 |
| Dyschoriste hirsutissima | (Nees) Kuntze | Acanthaceae | 8 |
| Dyschoriste schiedeana | (Nees) Kuntze | Acanthaceae | 8 |
| Dyssodia papposa | (Vent.) Hitchc. | Asteraceae | 8 |
| Dyssodia tagetiflora | Lag. | Asteraceae | 8 |
| Ebenopsis caesalpinioides | (Standl.) Britton & Rose | Fabaceae | 8 |
| Ebenopsis confinis | (Standl.) Britton & Rose | Fabaceae | 8 |
| Ebenopsis ebano | (Berland.) Barneby & J.W.Grimes | Fabaceae | 8 |
| Echeandia flavescens | (Schult. & Schult.f.) Cruden | Asparagaceae | 8 |
| Echeandia longipedicellata | Cruden | Asparagaceae | 8 |
| Echeveria subrigida | Rose | Crassulaceae | 8 |
| Echinocereus brandegeei | (J.M.Coult.) K.Schum. | Cactaceae | 8 |
| Echinocereus engelmannii | (Parry ex Engelm.) Lem. | Cactaceae | 8 |
| Echinocereus fendleri | (Engelm.) Sencke ex J.N.Haage | Cactaceae | 8 |
| Echinocereus nicholii | (L.D.Benson) B.D.Parfitt | Cactaceae | 8 |
| Echinocereus polyacanthus | Engelm. | Cactaceae | 8 |
| Echinocereus salm-dyckianus | Scheer | Cactaceae | 8 |
| Echinocereus santaritensis | W.Blum & Rutow | Cactaceae | 8 |
| Echinocereus sciurus | (K.Brandegee) Dams | Cactaceae | 8 |
| Echinodorus berteroi | (Spreng.) Fassett | Alismataceae | 8 |
| Echinopepon insularis | S.Watson | Cucurbitaceae | 8 |
| Echinopepon minimus | (Kellogg) S.Watson | Cucurbitaceae | 8 |
| Echinopepon wrightii | (A.Gray) S.Watson | Cucurbitaceae | 8 |
| Eclipta prostrata | (L.) L. | Asteraceae | 8 |
| Ehrendorferia chrysantha | (Hook. & Arn.) Rylander | Papaveraceae | 8 |
| Ehretia tinifolia | L. | Ehretiaceae | 8 |
| Elatine brachysperma | A.Gray | Elatinaceae | 8 |
| Eleocharis acicularis | (L.) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis atropurpurea | (Retz.) J.Presl & C.Presl | Cyperaceae | 8 |
| Eleocharis geniculata | (L.) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis macrostachya | Britton | Cyperaceae | 8 |
| Eleocharis montana | (Kunth) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis montevidensis | Kunth | Cyperaceae | 8 |
| Eleocharis parvula | (Roem. & Schult.) Link ex Bluff, Nees & Schauer | Cyperaceae | 8 |
| Eleocharis quinqueflora | (Hartmann) O.Schwarz | Cyperaceae | 8 |
| Eleocharis rostellata | (Torr.) Torr. | Cyperaceae | 8 |
| Elephantopus mollis | Kunth | Asteraceae | 8 |
| Elymus glaucus | Buckley | Poaceae | 8 |
| Elymus multisetus | (J.G.Sm.) Burtt Davy | Poaceae | 8 |
| Elymus violaceus | (Hornem.) J.Feilberg | Poaceae | 8 |
| Elytraria imbricata | (Vahl) Pers. | Acanthaceae | 8 |
| Emmenanthe penduliflora | Benth. | Hydrophyllaceae | 8 |
| Encelia actoni | Elmer | Asteraceae | 8 |
| Encelia asperifolia | (S.F.Blake) C.Clark & Kyhos | Asteraceae | 8 |
| Encelia californica | Nutt. | Asteraceae | 8 |
| Encelia densifolia | C.Clark & Kyhos | Asteraceae | 8 |
| Encelia farinosa | A.Gray ex Torr. | Asteraceae | 8 |
| Encelia frutescens | A.Gray | Asteraceae | 8 |
| Encelia ravenii | Wiggins | Asteraceae | 8 |
| Encelia stenophylla | Greene | Asteraceae | 8 |
| Encelia ventorum | Brandegee | Asteraceae | 8 |
| Enneapogon desvauxii | P.Beauv. | Poaceae | 8 |
| Enterolobium cyclocarpum | (Jacq.) Griseb. | Fabaceae | 8 |
| Ephedra antisyphilitica | Berland. ex C.A.Mey. | Ephedraceae | 8 |
| Ephedra aspera | Engelm. ex S.Watson | Ephedraceae | 8 |
| Ephedra californica | S.Watson | Ephedraceae | 8 |
| Ephedra nevadensis | S.Watson | Ephedraceae | 8 |
| Ephedra trifurca | Torr. ex S.Watson | Ephedraceae | 8 |
| Epidendrum cardiophorum | Schltr. | Orchidaceae | 8 |
| Epidendrum ciliare | L. | Orchidaceae | 8 |
| Epilobium canum | (Greene) P.H.Raven | Onagraceae | 8 |
| Epilobium ciliatum | Raf. | Onagraceae | 8 |
| Epilobium densiflorum | (Lindl.) Hoch & P.H.Raven | Onagraceae | 8 |
| Epipactis gigantea | Douglas | Orchidaceae | 8 |
| Equisetum hyemale | L. | Equisetaceae | 8 |
| Equisetum laevigatum | A.Braun | Equisetaceae | 8 |
| Equisetum myriochaetum | Schltdl. & Cham. | Equisetaceae | 8 |
| Eragrostis elliottii | (Elliott) S.Watson | Poaceae | 8 |
| Eragrostis hypnoides | (Lam.) Britton, Sterns & Poggenb. | Poaceae | 8 |
| Eragrostis intermedia | Hitchc. | Poaceae | 8 |
| Eragrostis pectinacea | (Michx.) Nees | Poaceae | 8 |
| Eragrostis secundiflora | J.Presl | Poaceae | 8 |
| Erblichia odorata | Seem. | Passifloraceae | 8 |
| Eremalche exilis | (A.Gray) Greene | Malvaceae | 8 |
| Eremalche rotundifolia | (A.Gray) Greene | Malvaceae | 8 |
| Eremocarya lepida | (A.Gray) Greene | Boraginaceae | 8 |
| Eremocarya micrantha | (Torr.) Greene | Boraginaceae | 8 |
| Eremogone eastwoodiae | (Rydb.) Ikonn. | Caryophyllaceae | 8 |
| Eremosis triflosculosa | (Kunth) Gleason | Asteraceae | 8 |
| Eremothera boothii | (Douglas) W.L.Wagner & Hoch | Onagraceae | 8 |
| Eremothera chamaenerioides | (A.Gray) W.L.Wagner & Hoch | Onagraceae | 8 |
| Eremothera refracta | (S.Watson) W.L.Wagner & Hoch | Onagraceae | 8 |
| Eriastrum densifolium | (Benth.) H.Mason | Polemoniaceae | 8 |
| Eriastrum diffusum | (A.Gray) H.Mason | Polemoniaceae | 8 |
| Eriastrum eremicum | (Jeps.) H.Mason | Polemoniaceae | 8 |
| Eriastrum filifolium | (Nutt.) Wooton & Standl. | Polemoniaceae | 8 |
| Eriastrum sapphirinum | (Eastw.) H.Mason | Polemoniaceae | 8 |
| Ericameria brachylepis | H.M.Hall | Asteraceae | 8 |
| Ericameria cooperi | H.M.Hall | Asteraceae | 8 |
| Ericameria cuneata | McClatchie | Asteraceae | 8 |
| Ericameria laricifolia | (A.Gray) Shinners | Asteraceae | 8 |
| Ericameria linearifolia | (DC.) Urbatsch & Wussow | Asteraceae | 8 |
| Ericameria nauseosa | (Pursh) G.L.Nesom & G.I.Baird | Asteraceae | 8 |
| Ericameria palmeri | (A.Gray) H.M.Hall | Asteraceae | 8 |
| Ericameria parishii | H.M.Hall | Asteraceae | 8 |
| Ericameria pinifolia | H.M.Hall | Asteraceae | 8 |
| Erigeron arizonicus | A.Gray | Asteraceae | 8 |
| Erigeron bonariensis | L. | Asteraceae | 8 |
| Erigeron breweri | A.Gray | Asteraceae | 8 |
| Erigeron canadensis | L. | Asteraceae | 8 |
| Erigeron divergens | Torr. & A.Gray | Asteraceae | 8 |
| Erigeron flagellaris | A.Gray | Asteraceae | 8 |
| Erigeron foliosus | Nutt. | Asteraceae | 8 |
| Erigeron galeottii | (A.Gray ex Hemsl.) Greene | Asteraceae | 8 |
| Erigeron modestus | A.Gray | Asteraceae | 8 |
| Erigeron neomexicanus | A.Gray | Asteraceae | 8 |
| Erigeron oreophilus | Greenm. | Asteraceae | 8 |
| Erigeron speciosus | (Lindl.) DC. | Asteraceae | 8 |
| Erigeron tracyi | Greene | Asteraceae | 8 |
| Erigeron variifolius | S.F.Blake | Asteraceae | 8 |
| Erigeron wislizeni | (A.Gray) Greene | Asteraceae | 8 |
| Eriochloa contracta | Hitchc. | Poaceae | 8 |
| Eriocoma coronata | (Thurb.) Romasch. | Poaceae | 8 |
| Eriocoma hymenoides | (Roem. & Schult.) Rydb. | Poaceae | 8 |
| Eriodictyon angustifolium | Nutt. | Namaceae | 8 |
| Eriodictyon crassifolium | Benth. | Namaceae | 8 |
| Eriodictyon parryi | (A.Gray) Greene | Namaceae | 8 |
| Eriodictyon sessilifolium | Greene | Namaceae | 8 |
| Eriodictyon trichocalyx | A.Heller | Namaceae | 8 |
| Eriogonum abertianum | Torr. | Polygonaceae | 8 |
| Eriogonum angulosum | Benth. | Polygonaceae | 8 |
| Eriogonum brachypodum | Torr. & A.Gray | Polygonaceae | 8 |
| Eriogonum clavatum | Small | Polygonaceae | 8 |
| Eriogonum davidsonii | Greene | Polygonaceae | 8 |
| Eriogonum deflexum | Torr. | Polygonaceae | 8 |
| Eriogonum deserticola | S.Watson | Polygonaceae | 8 |
| Eriogonum elongatum | Benth. | Polygonaceae | 8 |
| Eriogonum fasciculatum | Benth. | Polygonaceae | 8 |
| Eriogonum fastigiatum | Parry | Polygonaceae | 8 |
| Eriogonum gracile | Benth. | Polygonaceae | 8 |
| Eriogonum grande | Greene | Polygonaceae | 8 |
| Eriogonum inflatum | Torr. & Frém. | Polygonaceae | 8 |
| Eriogonum jamesii | Benth. | Polygonaceae | 8 |
| Eriogonum lonchophyllum | Torr. & A.Gray | Polygonaceae | 8 |
| Eriogonum maculatum | A.Heller | Polygonaceae | 8 |
| Eriogonum nudum | Douglas ex Benth. | Polygonaceae | 8 |
| Eriogonum parishii | S.Watson | Polygonaceae | 8 |
| Eriogonum polycladon | Benth. | Polygonaceae | 8 |
| Eriogonum preclarum | Reveal | Polygonaceae | 8 |
| Eriogonum reniforme | Torr. & Frém. | Polygonaceae | 8 |
| Eriogonum roseum | Durand & Hilg. | Polygonaceae | 8 |
| Eriogonum thomasii | Torr. | Polygonaceae | 8 |
| Eriogonum thurberi | Torr. | Polygonaceae | 8 |
| Eriogonum trichopes | Torr. | Polygonaceae | 8 |
| Eriogonum wrightii | Torr. ex Benth. | Polygonaceae | 8 |
| Eriophyllum confertiflorum | (DC.) A.Gray | Asteraceae | 8 |
| Eriophyllum lanatum | (Pursh) J.Forbes | Asteraceae | 8 |
| Eriophyllum lanosum | (A.Gray) A.Gray | Asteraceae | 8 |
| Eriophyllum pringlei | A.Gray | Asteraceae | 8 |
| Eriophyllum wallacei | A.Gray | Asteraceae | 8 |
| Erodium texanum | A.Gray | Geraniaceae | 8 |
| Errazurizia benthamii | (Brandegee) I.M.Johnst. | Fabaceae | 8 |
| Eryngium aristulatum | Jeps. | Apiaceae | 8 |
| Eryngium heterophyllum | Engelm. | Apiaceae | 8 |
| Eryngium lemmonii | J.M.Coult. & Rose | Apiaceae | 8 |
| Eryngium nasturtiifolium | F.Delaroche | Apiaceae | 8 |
| Erysimum asperum | (Nutt.) DC. | Brassicaceae | 8 |
| Erysimum suffrutescens | (Abrams) Rossbach | Brassicaceae | 8 |
| Erythranthe arvensis | (Greene) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe cardinalis | (Douglas ex Benth.) Spach | Phrymaceae | 8 |
| Erythranthe cordata | (Greene) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe diffusa | (A.L.Grant) N.S.Fraga | Phrymaceae | 8 |
| Erythranthe eastwoodiae | (Rydb.) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythranthe floribunda | (Lindl.) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe geyeri | (Torr.) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe glabrata | (Kunth) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe guttata | (DC.) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe lagunensis | G.L.Nesom | Phrymaceae | 8 |
| Erythranthe nasuta | (Greene) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe parishii | (Greene) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythranthe primuloides | (Benth.) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythranthe purpurea | N.S.Fraga | Phrymaceae | 8 |
| Erythranthe rubella | (A.Gray) N.S.Fraga | Phrymaceae | 8 |
| Erythranthe unimaculata | (Pennell) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe verbenacea | (Greene) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythrina americana | Mill. | Fabaceae | 8 |
| Erythrina flabelliformis | Kearney | Fabaceae | 8 |
| Erythrina lanata | Rose | Fabaceae | 8 |
| Erythrostemon mexicanus | (Rose) Gagnon & G.P.Lewis | Fabaceae | 8 |
| Erythrostemon palmeri | (S.Watson) Gagnon & G.P.Lewis | Fabaceae | 8 |
| Erythrostemon pannosus | (Brandegee) Gagnon & G.P.Lewis | Fabaceae | 8 |
| Erythrostemon placidus | (Brandegee) Gagnon & G.P.Lewis | Fabaceae | 8 |
| Erythroxylum havanense | Jacq. | Erythroxylaceae | 8 |
| Erythroxylum mexicanum | Kunth | Erythroxylaceae | 8 |
| Eschscholzia caespitosa | Benth. | Papaveraceae | 8 |
| Eschscholzia californica | Cham. | Papaveraceae | 8 |
| Eschscholzia minutiflora | S.Watson | Papaveraceae | 8 |
| Eschscholzia parishii | Greene | Papaveraceae | 8 |
| Eschscholzia ramosa | (Greene) Greene | Papaveraceae | 8 |
| Esenbeckia flava | Brandegee | Rutaceae | 8 |
| Eucnide cordata | (Kellogg) Kellogg ex Curran | Loasaceae | 8 |
| Eucnide urens | Parry ex Coville | Loasaceae | 8 |
| Eucrypta chrysanthemifolia | (Benth.) Greene | Hydrophyllaceae | 8 |
| Eucrypta micrantha | (Torr.) A.Heller | Hydrophyllaceae | 8 |
| Eugenia acapulcensis | Steud. | Myrtaceae | 8 |
| Eugenia capuli | (Schltdl. & Cham.) Hook. & Arn. | Myrtaceae | 8 |
| Eulobus californicus | Nutt. ex Torr. & A.Gray | Onagraceae | 8 |
| Eulobus crassifolius | (Greene) W.L.Wagner & Hoch | Onagraceae | 8 |
| Euphorbia abramsiana | L.C.Wheeler | Euphorbiaceae | 8 |
| Euphorbia albomarginata | Torr. & A.Gray | Euphorbiaceae | 8 |
| Euphorbia anthonyi | Brandegee | Euphorbiaceae | 8 |
| Euphorbia anychioides | Boiss. | Euphorbiaceae | 8 |
| Euphorbia ariensis | Kunth | Euphorbiaceae | 8 |
| Euphorbia arizonica | Engelm. | Euphorbiaceae | 8 |
| Euphorbia brachycera | Engelm. | Euphorbiaceae | 8 |
| Euphorbia californica | Benth. | Euphorbiaceae | 8 |
| Euphorbia capitellata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia chamaesula | Boiss. | Euphorbiaceae | 8 |
| Euphorbia colletioides | Benth. | Euphorbiaceae | 8 |
| Euphorbia cotinifolia | L. | Euphorbiaceae | 8 |
| Euphorbia crenulata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia davidii | Subils | Euphorbiaceae | 8 |
| Euphorbia dentosa | I.M.Johnst. | Euphorbiaceae | 8 |
| Euphorbia dioeca | Kunth | Euphorbiaceae | 8 |
| Euphorbia eriantha | Benth. | Euphorbiaceae | 8 |
| Euphorbia exstipulata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia florida | Engelm. | Euphorbiaceae | 8 |
| Euphorbia gracillima | S.Watson | Euphorbiaceae | 8 |
| Euphorbia graminea | Jacq. | Euphorbiaceae | 8 |
| Euphorbia heterophylla | L. | Euphorbiaceae | 8 |
| Euphorbia hindsiana | Benth. | Euphorbiaceae | 8 |
| Euphorbia hirta | L. | Euphorbiaceae | 8 |
| Euphorbia hypericifolia | L. | Euphorbiaceae | 8 |
| Euphorbia hyssopifolia | L. | Euphorbiaceae | 8 |
| Euphorbia indivisa | (Engelm.) Tidestr. | Euphorbiaceae | 8 |
| Euphorbia lata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia leucophylla | Benth. | Euphorbiaceae | 8 |
| Euphorbia lomelii | V.W.Steinm. | Euphorbiaceae | 8 |
| Euphorbia lurida | Engelm. | Euphorbiaceae | 8 |
| Euphorbia macropus | (Klotzsch & Garcke) Boiss. | Euphorbiaceae | 8 |
| Euphorbia maculata | L. | Euphorbiaceae | 8 |
| Euphorbia magdalenae | Benth. | Euphorbiaceae | 8 |
| Euphorbia melanadenia | Torr. | Euphorbiaceae | 8 |
| Euphorbia mendezii | Boiss. | Euphorbiaceae | 8 |
| Euphorbia micromera | Boiss. | Euphorbiaceae | 8 |
| Euphorbia misera | Benth. | Euphorbiaceae | 8 |
| Euphorbia nutans | Lag. | Euphorbiaceae | 8 |
| Euphorbia ophthalmica | Pers. | Euphorbiaceae | 8 |
| Euphorbia parishii | Greene | Euphorbiaceae | 8 |
| Euphorbia pediculifera | Engelm. | Euphorbiaceae | 8 |
| Euphorbia polycarpa | Benth. | Euphorbiaceae | 8 |
| Euphorbia prostrata | Aiton | Euphorbiaceae | 8 |
| Euphorbia pulcherrima | Willd. ex Klotzsch | Euphorbiaceae | 8 |
| Euphorbia radians | Benth. | Euphorbiaceae | 8 |
| Euphorbia revoluta | Engelm. | Euphorbiaceae | 8 |
| Euphorbia schiedeana | (Klotzsch & Garcke) Mayfield ex C.Nelson | Euphorbiaceae | 8 |
| Euphorbia schlechtendalii | Boiss. | Euphorbiaceae | 8 |
| Euphorbia serpens | Kunth | Euphorbiaceae | 8 |
| Euphorbia serpillifolia | Pers. | Euphorbiaceae | 8 |
| Euphorbia serrula | Engelm. | Euphorbiaceae | 8 |
| Euphorbia setiloba | Engelm. | Euphorbiaceae | 8 |
| Euphorbia spathulata | Lam. | Euphorbiaceae | 8 |
| Euphorbia stictospora | Engelm. | Euphorbiaceae | 8 |
| Euphorbia strigosa | Hook. & Arn. | Euphorbiaceae | 8 |
| Euphorbia thymifolia | L. | Euphorbiaceae | 8 |
| Euphorbia tomentulosa | S.Watson | Euphorbiaceae | 8 |
| Euphorbia villifera | Scheele | Euphorbiaceae | 8 |
| Euphorbia vizcainensis | Maya-Lastra & V.W.Steinm. | Euphorbiaceae | 8 |
| Euphorbia xanti | Engelm. ex Boiss. | Euphorbiaceae | 8 |
| Euphrosyne dealbata | (A.Gray) Panero | Asteraceae | 8 |
| Euploca convolvulacea | Nutt. | Heliotropiaceae | 8 |
| Euploca greggii | (Torr.) Halse & Feuillet | Heliotropiaceae | 8 |
| Euploca procumbens | (Mill.) Diane & Hilger | Heliotropiaceae | 8 |
| Eustoma exaltatum | (L.) Salisb. ex G.Don | Gentianaceae | 8 |
| Euthamia occidentalis | Nutt. | Asteraceae | 8 |
| Evolvulus alsinoides | (L.) L. | Convolvulaceae | 8 |
| Evolvulus arizonicus | A.Gray | Convolvulaceae | 8 |
| Evolvulus nummularius | (L.) L. | Convolvulaceae | 8 |
| Evolvulus prostratus | B.L.Rob. | Convolvulaceae | 8 |
| Evolvulus sericeus | Sw. | Convolvulaceae | 8 |
| Extriplex californica | (Moq.) E.H.Zacharias | Chenopodiaceae | 8 |
| Eysenhardtia orthocarpa | (A.Gray) S.Watson | Fabaceae | 8 |
| Eysenhardtia polystachya | (Ortega) Sarg. | Fabaceae | 8 |
| Fallugia paradoxa | (D.Don ex Tilloch & Taylor) Endl. ex Torr. | Rosaceae | 8 |
| Fendlera rupicola | A.Gray | Hydrangeaceae | 8 |
| Fendlerella utahensis | (S.Watson) A.Heller | Hydrangeaceae | 8 |
| Ferocactus acanthodes | (Lem.) Britton & Rose | Cactaceae | 8 |
| Ferocactus diguetii | (F.A.C.Weber) Britton & Rose | Cactaceae | 8 |
| Ferocactus emoryi | (Engelm.) Orcutt | Cactaceae | 8 |
| Ferocactus gracilis | H.E.Gates | Cactaceae | 8 |
| Ferocactus herrerae | J.G.Ortega | Cactaceae | 8 |
| Ferocactus peninsulae | (F.A.C.Weber) Britton & Rose | Cactaceae | 8 |
| Ferocactus townsendianus | Britton & Rose | Cactaceae | 8 |
| Ferocactus uncinatus | (Galeotti ex Pfeiff.) Britton & Rose | Cactaceae | 8 |
| Ferocactus viridescens | (Torr. & A.Gray) Britton & Rose | Cactaceae | 8 |
| Ferocactus wislizeni | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Festuca microstachys | Nutt. | Poaceae | 8 |
| Festuca octoflora | Walter | Poaceae | 8 |
| Ficus cotinifolia | Kunth | Moraceae | 8 |
| Ficus crocata | Mart. ex Miq. | Moraceae | 8 |
| Ficus insipida | Willd. | Moraceae | 8 |
| Ficus maxima | Mill. | Moraceae | 8 |
| Ficus obtusifolia | Kunth | Moraceae | 8 |
| Ficus pertusa | L.f. | Moraceae | 8 |
| Ficus petiolaris | Kunth | Moraceae | 8 |
| Fimbristylis complanata | (Retz.) Link | Cyperaceae | 8 |
| Fimbristylis cymosa | R.Br. | Cyperaceae | 8 |
| Fimbristylis dichotoma | (L.) Vahl | Cyperaceae | 8 |
| Fimbristylis littoralis | Gaudich. | Cyperaceae | 8 |
| Fimbristylis spadicea | (L.) Vahl | Cyperaceae | 8 |
| Fimbristylis thermalis | S.Watson | Cyperaceae | 8 |
| Fimbristylis vahlii | (Lam.) Link | Cyperaceae | 8 |
| Flaveria trinervia | (Spreng.) C.Mohr | Asteraceae | 8 |
| Fleischmannia pycnocephala | (Less.) R.M.King & H.Rob. | Asteraceae | 8 |
| Flourensia cernua | DC. | Asteraceae | 8 |
| Forchhammeria watsonii | Rose | Resedaceae | 8 |
| Forestiera angustifolia | Torr. | Oleaceae | 8 |
| Forestiera phillyreoides | (Benth.) Torr. | Oleaceae | 8 |
| Forestiera pubescens | Nutt. | Oleaceae | 8 |
| Forestiera rhamnifolia | Griseb. | Oleaceae | 8 |
| Fouquieria burragei | Rose | Fouquieriaceae | 8 |
| Fouquieria columnaris | (Kellogg) Kellogg ex Curran | Fouquieriaceae | 8 |
| Fouquieria diguetii | (Tiegh.) I.M.Johnst. | Fouquieriaceae | 8 |
| Fouquieria macdougalii | Nash | Fouquieriaceae | 8 |
| Fouquieria splendens | Engelm. | Fouquieriaceae | 8 |
| Fragaria vesca | L. | Rosaceae | 8 |
| Fragaria virginiana | Mill. | Rosaceae | 8 |
| Frangula californica | (Eschsch.) A.Gray | Rhamnaceae | 8 |
| Frangula mucronata | (Schltdl.) Grubov | Rhamnaceae | 8 |
| Frankenia palmeri | S.Watson | Frankeniaceae | 8 |
| Frankenia salina | (Molina) I.M.Johnst. | Frankeniaceae | 8 |
| Frasera parryi | Torr. | Gentianaceae | 8 |
| Frasera speciosa | Douglas ex Griseb. | Gentianaceae | 8 |
| Fraxinus dipetala | Hook. & Arn. | Oleaceae | 8 |
| Fraxinus greggii | A.Gray | Oleaceae | 8 |
| Fraxinus papillosa | Lingelsh. | Oleaceae | 8 |
| Fraxinus uhdei | (Wenz.) Lingelsh. | Oleaceae | 8 |
| Fraxinus velutina | Torr. | Oleaceae | 8 |
| Fremontodendron californicum | (Torr.) Coville | Malvaceae | 8 |
| Fremontodendron mexicanum | Davidson | Malvaceae | 8 |
| Fritillaria biflora | Lindl. | Liliaceae | 8 |
| Froelichia arizonica | Thornber ex Standl. | Amaranthaceae | 8 |
| Froelichia gracilis | (Hook.) Moq. | Amaranthaceae | 8 |
| Fuchsia arborescens | Sims | Onagraceae | 8 |
| Fuirena simplex | Vahl | Cyperaceae | 8 |
| Funastrum angustifolium | (Pers.) Liede & Meve | Apocynaceae | 8 |
| Funastrum arenarium | (Decne. ex Benth.) Liede | Apocynaceae | 8 |
| Funastrum clausum | (Jacq.) Schltr. | Apocynaceae | 8 |
| Funastrum crispum | (Benth.) Schltr. | Apocynaceae | 8 |
| Funastrum cynanchoides | (Decne.) Schltr. | Apocynaceae | 8 |
| Funastrum elegans | (Decne.) Schltr. | Apocynaceae | 8 |
| Funastrum heterophyllum | (Engelm. ex Torr.) Standl. | Apocynaceae | 8 |
| Funastrum pannosum | (Decne.) Schltr. | Apocynaceae | 8 |
| Funastrum peninsulare | (S.F.Blake) Liede & Meve | Apocynaceae | 8 |
| Funastrum utahense | (Engelm.) Liede & Meve | Apocynaceae | 8 |
| Gaga kaulfussii | (Kunze) Fay W.Li & Windham | Pteridaceae | 8 |
| Gaillardia mexicana | A.Gray | Asteraceae | 8 |
| Gaillardia pinnatifida | Torr. | Asteraceae | 8 |
| Gaillardia pulchella | Foug. | Asteraceae | 8 |
| Galactia striata | (Jacq.) Urb. | Fabaceae | 8 |
| Galactia wrightii | A.Gray | Fabaceae | 8 |
| Galinsoga parviflora | Cav. | Asteraceae | 8 |
| Galinsoga quadriradiata | Ruiz & Pav. | Asteraceae | 8 |
| Galium andrewsii | A.Gray | Rubiaceae | 8 |
| Galium angustifolium | Nutt. | Rubiaceae | 8 |
| Galium mexicanum | Kunth | Rubiaceae | 8 |
| Galium nuttallii | A.Gray | Rubiaceae | 8 |
| Galium porrigens | Dempster | Rubiaceae | 8 |
| Galium stellatum | Kellogg | Rubiaceae | 8 |
| Galium trifidum | L. | Rubiaceae | 8 |
| Galium wrightii | A.Gray | Rubiaceae | 8 |
| Galphimia angustifolia | Benth. | Malpighiaceae | 8 |
| Galphimia glauca | Cav. | Malpighiaceae | 8 |
| Galphimia gracilis | Bartl. | Malpighiaceae | 8 |
| Gambelia juncea | (Benth.) D.A.Sutton | Plantaginaceae | 8 |
| Gamochaeta americana | (Mill.) Wedd. | Asteraceae | 8 |
| Gamochaeta pensylvanica | (Willd.) Cabrera | Asteraceae | 8 |
| Gamochaeta purpurea | (L.) Cabrera | Asteraceae | 8 |
| Gamochaeta stagnalis | (I.M.Johnst.) Anderb. | Asteraceae | 8 |
| Garrya flavescens | S.Watson | Garryaceae | 8 |
| Garrya laurifolia | Benth. | Garryaceae | 8 |
| Garrya veatchii | Kellogg | Garryaceae | 8 |
| Garrya wrightii | Torr. | Garryaceae | 8 |
| Gaultheria erecta | Vent. | Ericaceae | 8 |
| Gaultheria myrsinoides | Kunth | Ericaceae | 8 |
| Gelsemium sempervirens | (L.) J.St.-Hil. | Gelsemiaceae | 8 |
| Gentiana bicuspidata | (G.Don) Briq. | Gentianaceae | 8 |
| Gentiana hooperi | J.S.Pringle | Gentianaceae | 8 |
| Geraea canescens | Torr. & A.Gray | Asteraceae | 8 |
| Geraea viscida | S.F.Blake | Asteraceae | 8 |
| Geranium caespitosum | E.James | Geraniaceae | 8 |
| Geranium californicum | G.N.Jones & F.F.Jones | Geraniaceae | 8 |
| Geranium carolinianum | L. | Geraniaceae | 8 |
| Geranium seemannii | Peyr. | Geraniaceae | 8 |
| Geranium wislizeni | S.Watson | Geraniaceae | 8 |
| Gilia achilleifolia | Benth. | Polemoniaceae | 8 |
| Gilia angelensis | V.E.Grant | Polemoniaceae | 8 |
| Gilia austrooccidentalis | (A.D.Grant & V.E.Grant) A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Gilia clivorum | (Jeps.) V.E.Grant | Polemoniaceae | 8 |
| Gilia diegensis | (Munz) A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Gilia flavocincta | A.Nelson | Polemoniaceae | 8 |
| Gilia lyndana | Allred | Polemoniaceae | 8 |
| Gilia mexicana | A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Gilia minor | A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Gilia ochroleuca | M.E.Jones | Polemoniaceae | 8 |
| Gilia scopulorum | M.E.Jones | Polemoniaceae | 8 |
| Gilia sinuata | Douglas ex Benth. | Polemoniaceae | 8 |
| Gilia stellata | A.Heller | Polemoniaceae | 8 |
| Giliastrum rigidulum | Rydb. | Polemoniaceae | 8 |
| Githopsis diffusa | A.Gray | Campanulaceae | 8 |
| Gleditsia triacanthos | L. | Fabaceae | 8 |
| Glinus radiatus | (Ruiz & Pav.) Rohrb. | Molluginaceae | 8 |
| Gliricidia sepium | (Jacq.) Kunth | Fabaceae | 8 |
| Glossopetalon spinescens | A.Gray | Crossosomataceae | 8 |
| Glossostipula blepharophylla | (Standl.) Lorence | Rubiaceae | 8 |
| Glyceria striata | (Lam.) Hitchc. | Poaceae | 8 |
| Gnaphalium palustre | Nutt. | Asteraceae | 8 |
| Gomphrena caespitosa | Torr. | Amaranthaceae | 8 |
| Gomphrena lanuparonychioides | T. Ortuño & Borsch | Amaranthaceae | 8 |
| Gomphrena serrata | L. | Amaranthaceae | 8 |
| Gomphrena sonorae | Torr. ex Emory | Amaranthaceae | 8 |
| Gomphrena vermicularis | L. | Amaranthaceae | 8 |
| Gonolobus barbatus | Kunth | Apocynaceae | 8 |
| Gonolobus erianthus | Decne. | Apocynaceae | 8 |
| Gonolobus grandiflorus | (Cav.) Schult. | Apocynaceae | 8 |
| Gonolobus naturalistae | M.G.Chávez, Pío-León & L.O.Alvarado | Apocynaceae | 8 |
| Gonolobus uniflorus | Kunth | Apocynaceae | 8 |
| Goodyera striata | Rchb.f. | Orchidaceae | 8 |
| Gossypium aridum | (Rose & Standl.) Skovsted | Malvaceae | 8 |
| Gossypium harknessii | Brandegee | Malvaceae | 8 |
| Gossypium hirsutum | L. | Malvaceae | 8 |
| Gossypium klotzschianum | Andersson | Malvaceae | 8 |
| Gossypium thurberi | Tod. | Malvaceae | 8 |
| Gouania lupuloides | (L.) Urb. | Rhamnaceae | 8 |
| Gouania rosei | Wiggins | Rhamnaceae | 8 |
| Govenia dressleriana | E.W.Greenw. | Orchidaceae | 8 |
| Grindelia hirsutula | Hook. & Arn. | Asteraceae | 8 |
| Grona triflora | (L.) H.Ohashi & K.Ohashi | Fabaceae | 8 |
| Gronovia scandens | L. | Loasaceae | 8 |
| Grusonia emoryi | (Engelm.) Pinkava | Cactaceae | 8 |
| Grusonia invicta | (K.Brandegee) E.F.Anderson | Cactaceae | 8 |
| Grusonia kunzei | (Rose) Pinkava | Cactaceae | 8 |
| Guaiacum coulteri | A.Gray | Zygophyllaceae | 8 |
| Guardiola platyphylla | A.Gray | Asteraceae | 8 |
| Guarianthe aurantiaca | (Bateman ex Lindl.) Dressler & W.E.Higgins | Orchidaceae | 8 |
| Guazuma ulmifolia | Lam. | Malvaceae | 8 |
| Guilleminea densa | (Humb. & Bonpl. ex Schult.) Moq. | Amaranthaceae | 8 |
| Gutierrezia californica | (DC.) Torr. & A.Gray | Asteraceae | 8 |
| Gutierrezia conoidea | (Hemsl.) M.A.Lane | Asteraceae | 8 |
| Gutierrezia microcephala | (DC.) A.Gray | Asteraceae | 8 |
| Gutierrezia sarothrae | (Pursh) Britton & Rusby | Asteraceae | 8 |
| Gymnosperma glutinosum | (Spreng.) Less. | Asteraceae | 8 |
| Gyrocarpus jatrophifolius | Domin | Hernandiaceae | 8 |
| Habenaria lucaecapensis | Fernald | Orchidaceae | 8 |
| Habenaria macroceratitis | Willd. | Orchidaceae | 8 |
| Habranthus longifolius | (Hemsl.) Flagg, G.Lom.Sm. & Meerow | Amaryllidaceae | 8 |
| Haematoxylum brasiletto | H.Karst. | Fabaceae | 8 |
| Halerpestes cymbalaria | Greene | Ranunculaceae | 8 |
| Hamelia patens | Jacq. | Rubiaceae | 8 |
| Hamelia xorullensis | Kunth | Rubiaceae | 8 |
| Haplophyton crooksii | (L.D.Benson) L.D.Benson | Apocynaceae | 8 |
| Harfordia macroptera | (Benth.) Parry | Polygonaceae | 8 |
| Harpagonella palmeri | A.Gray | Boraginaceae | 8 |
| Havardia pallens | (Benth.) Britton & Rose | Fabaceae | 8 |
| Hazardia berberidis | Greene | Asteraceae | 8 |
| Hazardia cana | Greene | Asteraceae | 8 |
| Hazardia orcuttii | Greene | Asteraceae | 8 |
| Hazardia squarrosa | (Hook. & Arn.) Greene | Asteraceae | 8 |
| Hazardia stenolepis | (Hall) Hoover | Asteraceae | 8 |
| Hebecarpa barbeyana | (Chodat) J.R.Abbott | Polygalaceae | 8 |
| Hebecarpa macradenia | (A.Gray) J.R.Abbott | Polygalaceae | 8 |
| Hebecarpa obscura | (Benth.) J.R.Abbott | Polygalaceae | 8 |
| Hechtia montana | Brandegee | Bromeliaceae | 8 |
| Hedeoma dentata | Torr. | Lamiaceae | 8 |
| Hedeoma drummondii | Benth. | Lamiaceae | 8 |
| Hedeoma hyssopifolia | A.Gray | Lamiaceae | 8 |
| Hedeoma oblongifolia | (A.Gray) A.Heller | Lamiaceae | 8 |
| Hedosyne ambrosiifolia | (A.Gray) Strother | Asteraceae | 8 |
| Hedyosmum mexicanum | C.Cordem. | Chloranthaceae | 8 |
| Heimia salicifolia | Link | Lythraceae | 8 |
| Helenium mexicanum | Kunth | Asteraceae | 8 |
| Helenium puberulum | DC. | Asteraceae | 8 |
| Helenium thurberi | A.Gray | Asteraceae | 8 |
| Helianthella quinquenervis | (Hook.) A.Gray | Asteraceae | 8 |
| Helianthus annuus | L. | Asteraceae | 8 |
| Helianthus californicus | DC. | Asteraceae | 8 |
| Helianthus ciliaris | DC. | Asteraceae | 8 |
| Helianthus gracilentus | A.Gray | Asteraceae | 8 |
| Helianthus laciniatus | A.Gray | Asteraceae | 8 |
| Helianthus niveus | (Benth.) Brandegee | Asteraceae | 8 |
| Helianthus petiolaris | Nutt. | Asteraceae | 8 |
| Helicteres baruensis | Jacq. | Malvaceae | 8 |
| Helicteres guazumifolia | Kunth | Malvaceae | 8 |
| Heliocarpus terebinthinaceus | (DC.) Hochr. | Malvaceae | 8 |
| Heliomeris longifolia | Cockerell | Asteraceae | 8 |
| Heliomeris multiflora | Nutt. | Asteraceae | 8 |
| Heliopsis annua | Hemsl. | Asteraceae | 8 |
| Heliopsis buphthalmoides | Dunal | Asteraceae | 8 |
| Heliopsis parvifolia | A.Gray | Asteraceae | 8 |
| Heliotropium angiospermum | Murray | Heliotropiaceae | 8 |
| Heliotropium curassavicum | L. | Heliotropiaceae | 8 |
| Heliotropium verdcourtii | Craven | Heliotropiaceae | 8 |
| Hemionitis palmata | L. | Pteridaceae | 8 |
| Henrya insularis | Nees | Acanthaceae | 8 |
| Herissantia crispa | (L.) Brizicky | Malvaceae | 8 |
| Hermannia palmeri | Rose | Malvaceae | 8 |
| Hesperalbizia occidentalis | (Brandegee) Barneby & J.W.Grimes | Fabaceae | 8 |
| Hesperidanthus linearifolius | (A.Gray) Rydb. | Brassicaceae | 8 |
| Hesperocallis undulata | A.Gray | Asparagaceae | 8 |
| Hesperochiron nanus | (Lindl.) Greene | Hydrophyllaceae | 8 |
| Hesperocnide tenella | Torr. | Urticaceae | 8 |
| Hesperocyparis arizonica | (Greene) Bartel | Cupressaceae | 8 |
| Hesperocyparis forbesii | (Jeps.) Bartel | Cupressaceae | 8 |
| Hesperocyparis lusitanica | (Mill.) Bartel | Cupressaceae | 8 |
| Hesperocyparis revealiana | (Silba) Silba | Cupressaceae | 8 |
| Hesperostipa comata | (Trin. & Rupr.) Barkworth | Poaceae | 8 |
| Hesperostipa neomexicana | (Thurb.) Barkworth | Poaceae | 8 |
| Hesperoyucca whipplei | (Torr.) Trel. | Asparagaceae | 8 |
| Heteranthera limosa | (Sw.) Willd. | Pontederiaceae | 8 |
| Heterocentron subtriplinervium | (Link & Otto) A.Braun & C.D.Bouché | Melastomataceae | 8 |
| Heterocodon rariflorus | Nutt. | Campanulaceae | 8 |
| Heteropogon contortus | (L.) P.Beauv. ex Roem. & Schult. | Poaceae | 8 |
| Heteropogon melanocarpus | (Elliott) Benth. | Poaceae | 8 |
| Heteropterys brachiata | (L.) DC. | Malpighiaceae | 8 |
| Heterosperma pinnatum | Cav. | Asteraceae | 8 |
| Heterotheca fastigiata | (Greene) V.L.Harms | Asteraceae | 8 |
| Heterotheca fulcrata | (Greene) Shinners | Asteraceae | 8 |
| Heterotheca grandiflora | Nutt. | Asteraceae | 8 |
| Heterotheca inuloides | Cass. | Asteraceae | 8 |
| Heterotheca sessiliflora | (Nutt.) Shinners | Asteraceae | 8 |
| Heterotheca subaxillaris | (Lam.) Britton & Rusby | Asteraceae | 8 |
| Heuchera brevistaminea | Wiggins | Saxifragaceae | 8 |
| Heuchera parvifolia | Nutt. ex Torr. & A.Gray | Saxifragaceae | 8 |
| Heuchera rubescens | Torr. | Saxifragaceae | 8 |
| Heuchera sanguinea | Engelm. | Saxifragaceae | 8 |
| Hexasepalum teres | (Walter) J.H.Kirkbr. | Rubiaceae | 8 |
| Hibiscus acicularis | Standl. | Malvaceae | 8 |
| Hibiscus coulteri | Harv. ex A.Gray | Malvaceae | 8 |
| Hibiscus denudatus | Benth. | Malvaceae | 8 |
| Hibiscus phoeniceus | Jacq. | Malvaceae | 8 |
| Hibiscus ribifolius | A.Gray | Malvaceae | 8 |
| Hibiscus tiliaceus | L. | Malvaceae | 8 |
| Hieracium abscissum | Less. | Asteraceae | 8 |
| Hieracium albiflorum | Hook. | Asteraceae | 8 |
| Hieracium bolanderi | A.Gray | Asteraceae | 8 |
| Hieracium fendleri | Sch.Bip. | Asteraceae | 8 |
| Hilaria belangeri | (Steud.) Nash | Poaceae | 8 |
| Hilaria mutica | (Buckley) Benth. | Poaceae | 8 |
| Hilaria rigida | (Thurb.) Benth. ex Scribn. | Poaceae | 8 |
| Hintonia latiflora | (Sessé & Moc. ex DC.) Bullock | Rubiaceae | 8 |
| Hippocratea volubilis | L. | Celastraceae | 8 |
| Hippuris vulgaris | L. | Plantaginaceae | 8 |
| Hoffmannseggia drepanocarpa | A.Gray | Fabaceae | 8 |
| Hoffmannseggia glauca | (Ortega) Eifert | Fabaceae | 8 |
| Hoffmannseggia microphylla | Torr. | Fabaceae | 8 |
| Hofmeisteria fasciculata | (Benth.) Walp. | Asteraceae | 8 |
| Hoita macrostachya | (DC.) Rydb. | Fabaceae | 8 |
| Hoita orbicularis | (Lindl.) Rydb. | Fabaceae | 8 |
| Holocarpha virgata | (A.Gray) D.D.Keck | Asteraceae | 8 |
| Holodiscus discolor | (Pursh) Maxim. | Rosaceae | 8 |
| Homalocephala parryi | (Engelm.) Vargas & Bárcenas | Cactaceae | 8 |
| Hooveria parviflora | (S.Watson) D.W.Taylor & D.J.Keil | Asparagaceae | 8 |
| Hopia obtusa | (Kunth) Zuloaga & Morrone | Poaceae | 8 |
| Hordeum brachyantherum | Nevski | Poaceae | 8 |
| Hordeum depressum | (Scribn. & J.G.Sm.) Rydb. | Poaceae | 8 |
| Hordeum jubatum | L. | Poaceae | 8 |
| Horsfordia alata | (S.Watson) A.Gray | Malvaceae | 8 |
| Horsfordia newberryi | (S.Watson) A.Gray | Malvaceae | 8 |
| Hosackia crassifolia | Benth. | Fabaceae | 8 |
| Hosackia oblongifolia | Benth. | Fabaceae | 8 |
| Houstonia rubra | Cav. | Rubiaceae | 8 |
| Hulsea californica | A.Gray | Asteraceae | 8 |
| Hulsea mexicana | Rydb. | Asteraceae | 8 |
| Hulsea vestita | A.Gray | Asteraceae | 8 |
| Hura polyandra | Baill. | Euphorbiaceae | 8 |
| Hybanthus fruticulosus | (Benth.) I.M.Johnst. | Violaceae | 8 |
| Hydrocotyle ranunculoides | L.f. | Araliaceae | 8 |
| Hydrocotyle umbellata | L. | Araliaceae | 8 |
| Hydrocotyle verticillata | Thunb. | Araliaceae | 8 |
| Hydrolea spinosa | L. | Hydroleaceae | 8 |
| Hymenachne amplexicaulis | (Rudge) Nees | Poaceae | 8 |
| Hymenaea courbaril | L. | Fabaceae | 8 |
| Hymenopappus filifolius | Hook. | Asteraceae | 8 |
| Hymenopappus mexicanus | A.Gray | Asteraceae | 8 |
| Hymenostephium cordatum | S.F.Blake | Asteraceae | 8 |
| Hymenothrix dissecta | (A.Gray) B.G.Baldwin | Asteraceae | 8 |
| Hymenothrix pedata | (A.Gray) B.G.Baldwin | Asteraceae | 8 |
| Hymenothrix wislizeni | A.Gray | Asteraceae | 8 |
| Hymenothrix wrightii | A.Gray | Asteraceae | 8 |
| Hymenoxys odorata | DC. | Asteraceae | 8 |
| Hypericum anagalloides | Cham. & Schltdl. | Hypericaceae | 8 |
| Hypericum parvulum | Greene | Hypericaceae | 8 |
| Hypericum scouleri | Hook. | Hypericaceae | 8 |
| Hypopitys monotropa | Crantz | Ericaceae | 8 |
| Hyptis capitata | Jacq. | Lamiaceae | 8 |
| Ibervillea sonorae | (S.Watson) Greene | Cucurbitaceae | 8 |
| Ibervillea tenuisecta | (A.Gray) Small | Cucurbitaceae | 8 |
| Ilex brandegeeana | Loes. | Aquifoliaceae | 8 |
| Ilex cassine | L. | Aquifoliaceae | 8 |
| Indigofera fruticosa | Rose | Fabaceae | 8 |
| Indigofera miniata | Ortega | Fabaceae | 8 |
| Indigofera suffruticosa | Mill. | Fabaceae | 8 |
| Inga laurina | (Sw.) Willd. | Fabaceae | 8 |
| Inga vera | Willd. | Fabaceae | 8 |
| Iostephane heterophylla | Benth. | Asteraceae | 8 |
| Ipomoea alba | L. | Convolvulaceae | 8 |
| Ipomoea ampullacea | Fernald | Convolvulaceae | 8 |
| Ipomoea arborescens | (Humb. & Bonpl. ex Willd.) G.Don | Convolvulaceae | 8 |
| Ipomoea aristolochiifolia | G.Don | Convolvulaceae | 8 |
| Ipomoea barbatisepala | A.Gray | Convolvulaceae | 8 |
| Ipomoea bracteata | Cav. | Convolvulaceae | 8 |
| Ipomoea capillacea | (Kunth) G.Don | Convolvulaceae | 8 |
| Ipomoea cardiophylla | A.Gray | Convolvulaceae | 8 |
| Ipomoea carnea | Jacq. | Convolvulaceae | 8 |
| Ipomoea cholulensis | Kunth | Convolvulaceae | 8 |
| Ipomoea corymbosa | (L.) Roth | Convolvulaceae | 8 |
| Ipomoea costellata | Torr. | Convolvulaceae | 8 |
| Ipomoea cristulata | Hallier f. | Convolvulaceae | 8 |
| Ipomoea dumosa | (Benth.) L.O.Williams | Convolvulaceae | 8 |
| Ipomoea hartwegii | Benth. | Convolvulaceae | 8 |
| Ipomoea hederacea | Jacq. | Convolvulaceae | 8 |
| Ipomoea hederifolia | L. | Convolvulaceae | 8 |
| Ipomoea heptaphylla | Sweet | Convolvulaceae | 8 |
| Ipomoea imperati | (Vahl) Griseb. | Convolvulaceae | 8 |
| Ipomoea intrapilosa | Rose | Convolvulaceae | 8 |
| Ipomoea jalapa | (L.) Pursh | Convolvulaceae | 8 |
| Ipomoea laeta | A.Gray | Convolvulaceae | 8 |
| Ipomoea lindenii | M.Martens & Galeotti | Convolvulaceae | 8 |
| Ipomoea longifolia | Benth. | Convolvulaceae | 8 |
| Ipomoea mairetii | Choisy | Convolvulaceae | 8 |
| Ipomoea meyeri | (Spreng.) G.Don | Convolvulaceae | 8 |
| Ipomoea microsepala | Benth. | Convolvulaceae | 8 |
| Ipomoea minutiflora | (M.Martens & Galeotti) House | Convolvulaceae | 8 |
| Ipomoea muricata | (L.) Jacq. | Convolvulaceae | 8 |
| Ipomoea neei | (Spreng.) O'Donell | Convolvulaceae | 8 |
| Ipomoea nil | (L.) Roth | Convolvulaceae | 8 |
| Ipomoea orizabensis | (G.Pelletan) Ledeb. ex Steud. | Convolvulaceae | 8 |
| Ipomoea parasitica | (Kunth) G.Don | Convolvulaceae | 8 |
| Ipomoea pedicellaris | Benth. | Convolvulaceae | 8 |
| Ipomoea pes-caprae | (L.) R.Br. | Convolvulaceae | 8 |
| Ipomoea plummerae | A.Gray | Convolvulaceae | 8 |
| Ipomoea pubescens | Lam. | Convolvulaceae | 8 |
| Ipomoea purpurea | (L.) Roth | Convolvulaceae | 8 |
| Ipomoea quamoclit | L. | Convolvulaceae | 8 |
| Ipomoea scopulorum | Brandegee | Convolvulaceae | 8 |
| Ipomoea seducta | House | Convolvulaceae | 8 |
| Ipomoea sescossiana | Baill. | Convolvulaceae | 8 |
| Ipomoea suaveolens | (M.Martens & Galeotti) Hemsl. | Convolvulaceae | 8 |
| Ipomoea tastensis | Brandegee | Convolvulaceae | 8 |
| Ipomoea ternifolia | Cav. | Convolvulaceae | 8 |
| Ipomoea trifida | (Kunth) G.Don | Convolvulaceae | 8 |
| Ipomoea triloba | L. | Convolvulaceae | 8 |
| Ipomopsis aggregata | (Pursh) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis longiflora | (Torr.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis macombii | (Torr. ex A.Gray) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis polycladon | (Torr.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis tenuifolia | (A.Gray) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis thurberi | (A.Gray) V.E.Grant | Polemoniaceae | 8 |
| Iresine ajuscana | Suess. & Beyerle ex Suess. | Amaranthaceae | 8 |
| Iresine calea | (Ibáñez) Standl. | Amaranthaceae | 8 |
| Iresine diffusa | Humb. & Bonpl. ex Willd. | Amaranthaceae | 8 |
| Iresine heterophylla | Standl. | Amaranthaceae | 8 |
| Iresine rhizomatosa | Standl. | Amaranthaceae | 8 |
| Isocoma acradenia | (Greene) Greene | Asteraceae | 8 |
| Isocoma coronopifolia | Greene | Asteraceae | 8 |
| Isocoma pluriflora | (Torr. & A.Gray) Greene | Asteraceae | 8 |
| Isocoma tenuisecta | Greene | Asteraceae | 8 |
| Isoetes howellii | Engelm. | Isoetaceae | 8 |
| Isoetes orcuttii | A.A.Eaton | Isoetaceae | 8 |
| Isolepis cernua | (Vahl) Roem. & Schult. | Cyperaceae | 8 |
| Iva hayesiana | A.Gray | Asteraceae | 8 |
| Jacaratia mexicana | A.DC. | Caricaceae | 8 |
| Jacquemontia abutiloides | Benth. | Convolvulaceae | 8 |
| Jacquemontia eastwoodiana | I.M.Johnst. | Convolvulaceae | 8 |
| Jacquemontia evolvuloides | Meisn. | Convolvulaceae | 8 |
| Jacquemontia nodiflora | (Desr.) G.Don | Convolvulaceae | 8 |
| Jacquemontia pringlei | A.Gray | Convolvulaceae | 8 |
| Jacquemontia tamnifolia | (L.) Griseb. | Convolvulaceae | 8 |
| Jaegeria hirta | (Lag.) Less. | Asteraceae | 8 |
| Jaltomata procumbens | (Cav.) J.L.Gentry | Solanaceae | 8 |
| Jatropha cardiophylla | (Torr.) Müll.Arg. | Euphorbiaceae | 8 |
| Jatropha cinerea | (Ortega) Müll.Arg. | Euphorbiaceae | 8 |
| Jatropha cordata | (Ortega) Müll.Arg. | Euphorbiaceae | 8 |
| Jatropha cuneata | Wiggins & Rollins | Euphorbiaceae | 8 |
| Jatropha gossypiifolia | L. | Euphorbiaceae | 8 |
| Jatropha macrorhiza | Benth. | Euphorbiaceae | 8 |
| Jatropha peltata | Sessé | Euphorbiaceae | 8 |
| Jatropha vernicosa | Brandegee | Euphorbiaceae | 8 |
| Jaumea carnosa | (Less.) A.Gray | Asteraceae | 8 |
| Jepsonia parryi | (Torr.) Small | Saxifragaceae | 8 |
| Johnstonella albida | (Kunth) M.E.Mabry & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella angustifolia | (Torr.) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella costata | (Brandegee) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella holoptera | (A.Gray) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella mexicana | (Brandegee) M.E.Mabry & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella pusilla | (Torr. & A.Gray) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella racemosa | (S.Watson ex A.Gray) Brand | Boraginaceae | 8 |
| Jouvea pilosa | (J.Presl) Scribn. | Poaceae | 8 |
| Juglans major | (Torr.) A.Heller | Juglandaceae | 8 |
| Juncus acuminatus | Michx. | Juncaceae | 8 |
| Juncus acutus | L. | Juncaceae | 8 |
| Juncus articulatus | L. | Juncaceae | 8 |
| Juncus balticus | Willd. | Juncaceae | 8 |
| Juncus bufonius | L. | Juncaceae | 8 |
| Juncus cooperi | Engelm. | Juncaceae | 8 |
| Juncus dichotomus | Elliott | Juncaceae | 8 |
| Juncus dubius | Engelm. | Juncaceae | 8 |
| Juncus effusus | L. | Juncaceae | 8 |
| Juncus ensifolius | Wikstr. | Juncaceae | 8 |
| Juncus interior | Wiegand | Juncaceae | 8 |
| Juncus kelloggii | Engelm. | Juncaceae | 8 |
| Juncus marginatus | Rostk. | Juncaceae | 8 |
| Juncus mertensianus | Bong. | Juncaceae | 8 |
| Juncus microcephalus | Kunth | Juncaceae | 8 |
| Juncus nodosus | L. | Juncaceae | 8 |
| Juncus occidentalis | (Coville) Wiegand | Juncaceae | 8 |
| Juncus parryi | Engelm. | Juncaceae | 8 |
| Juncus patens | E.Mey. | Juncaceae | 8 |
| Juncus phaeocephalus | Engelm. | Juncaceae | 8 |
| Juncus tenuis | Willd. | Juncaceae | 8 |
| Juncus torreyi | Coville | Juncaceae | 8 |
| Juncus xiphioides | E.Mey. | Juncaceae | 8 |
| Juniperus arizonica | (R.P.Adams) R.P.Adams | Cupressaceae | 8 |
| Juniperus californica | Carrière | Cupressaceae | 8 |
| Juniperus deppeana | Steud. | Cupressaceae | 8 |
| Juniperus durangensis | Martínez | Cupressaceae | 8 |
| Juniperus flaccida | Schltdl. | Cupressaceae | 8 |
| Juniperus pinchotii | Sudw. | Cupressaceae | 8 |
| Juniperus scopulorum | Sarg. | Cupressaceae | 8 |
| Justicia californica | (Benth.) D.N.Gibson | Acanthaceae | 8 |
| Justicia longii | Hilsenb. | Acanthaceae | 8 |
| Justicia pacifica | (Oerst.) Hemsl. | Acanthaceae | 8 |
| Justicia palmeri | Rose | Acanthaceae | 8 |
| Justicia purpusii | (Brandegee) D.N.Gibson | Acanthaceae | 8 |
| Justicia spicigera | Schltdl. | Acanthaceae | 8 |
| Kallstroemia californica | (S.Watson) Vail | Zygophyllaceae | 8 |
| Kallstroemia grandiflora | Torr. ex A.Gray | Zygophyllaceae | 8 |
| Kallstroemia maxima | (L.) Hook. & Arn. | Zygophyllaceae | 8 |
| Kallstroemia parviflora | Norton | Zygophyllaceae | 8 |
| Kallstroemia peninsularis | D.M.Porter | Zygophyllaceae | 8 |
| Kallstroemia rosei | Rydb. | Zygophyllaceae | 8 |
| Kearnemalvastrum subtriflorum | (Lag.) D.M.Bates | Malvaceae | 8 |
| Keckiella antirrhinoides | (Benth.) Straw | Plantaginaceae | 8 |
| Keckiella cordifolia | (Benth.) Straw | Plantaginaceae | 8 |
| Keckiella ternata | (Torr. ex A.Gray) Straw | Plantaginaceae | 8 |
| Koeberlinia spinosa | Zucc. | Koeberliniaceae | 8 |
| Koeleria macrantha | (Ledeb.) Schult. | Poaceae | 8 |
| Kopsiopsis strobilacea | (A.Gray) Beck | Orobanchaceae | 8 |
| Kosteletzkya depressa | (L.) O.J.Blanch., Fryxell & D.M.Bates | Malvaceae | 8 |
| Krameria bicolor | S.Watson | Krameriaceae | 8 |
| Krameria erecta | Willd. | Krameriaceae | 8 |
| Krameria ixine | L. | Krameriaceae | 8 |
| Krameria ramosissima | S.Watson | Krameriaceae | 8 |
| Krascheninnikovia ceratoides | (L.) Gueldenst. | Chenopodiaceae | 8 |
| Lacistema aggregatum | (P.J.Bergius) Rusby | Lacistemataceae | 8 |
| Lactuca graminifolia | Michx. | Asteraceae | 8 |
| Lactuca oblongifolia | Nutt. | Asteraceae | 8 |
| Laelia albida | Bateman ex Lindl. | Orchidaceae | 8 |
| Laennecia coulteri | (A.Gray) G.L.Nesom | Asteraceae | 8 |
| Laennecia filaginoides | DC. | Asteraceae | 8 |
| Laennecia schiedeana | (Less.) G.L.Nesom | Asteraceae | 8 |
| Laennecia sophiifolia | (Kunth) G.L.Nesom | Asteraceae | 8 |
| Lagascea decipiens | Hemsl. | Asteraceae | 8 |
| Lagascea helianthifolia | Kunth | Asteraceae | 8 |
| Laguncularia racemosa | (L.) C.F.Gaertn. | Combretaceae | 8 |
| Lamourouxia multifida | Kunth | Orobanchaceae | 8 |
| Lamourouxia rhinanthifolia | Kunth | Orobanchaceae | 8 |
| Lamourouxia viscosa | Kunth | Orobanchaceae | 8 |
| Langloisia setosissima | (Torr. & A.Gray) Greene | Polemoniaceae | 8 |
| Lantana achyranthifolia | Desf. | Verbenaceae | 8 |
| Lantana camara | L. | Verbenaceae | 8 |
| Lantana involucrata | L. | Verbenaceae | 8 |
| Lantana urticoides | Hayek | Verbenaceae | 8 |
| Lantana velutina | M.Martens & Galeotti | Verbenaceae | 8 |
| Lappula occidentalis | (S.Watson) Greene | Boraginaceae | 8 |
| Larrea tridentata | (DC.) Coville | Zygophyllaceae | 8 |
| Lasiacis divaricata | (L.) Hitchc. | Poaceae | 8 |
| Lasiacis ruscifolia | (Kunth) Hitchc. ex Chase | Poaceae | 8 |
| Lasianthaea fruticosa | (L.) K.M.Becker | Asteraceae | 8 |
| Lasianthaea podocephala | (A.Gray) K.M.Becker | Asteraceae | 8 |
| Lasianthaea rosei | (Greenm.) McVaugh | Asteraceae | 8 |
| Lastarriaea coriacea | (Goodman) Hoover | Polygonaceae | 8 |
| Lasthenia coronaria | (Nutt.) Ornduff | Asteraceae | 8 |
| Lasthenia glabrata | Lindl. | Asteraceae | 8 |
| Lasthenia gracilis | (DC.) Greene | Asteraceae | 8 |
| Lathyrus graminifolius | (S.Watson) T.G.White | Fabaceae | 8 |
| Lathyrus lanszwertii | Kellogg | Fabaceae | 8 |
| Lathyrus splendens | Kellogg | Fabaceae | 8 |
| Lathyrus vestitus | Nutt. | Fabaceae | 8 |
| Layia glandulosa | (Hook.) Hook. & Arn. | Asteraceae | 8 |
| Layia platyglossa | (Fisch. & C.A.Mey.) A.Gray | Asteraceae | 8 |
| Leibnitzia lyrata | (Sch.Bip.) G.L.Nesom | Asteraceae | 8 |
| Lemna aequinoctialis | Welw. | Araceae | 8 |
| Lemna gibba | L. | Araceae | 8 |
| Lemna minor | L. | Araceae | 8 |
| Lemna minuta | Kunth | Araceae | 8 |
| Lennoa madreporoides | Lex. | Lennoaceae | 8 |
| Lepechinia cardiophylla | Epling | Lamiaceae | 8 |
| Lepechinia caulescens | (Ortega) Epling | Lamiaceae | 8 |
| Lepechinia ganderi | Epling | Lamiaceae | 8 |
| Lepechinia hastata | (A.Gray) Epling | Lamiaceae | 8 |
| Lepidium acutidens | (A.Gray) Howell | Brassicaceae | 8 |
| Lepidium alyssoides | A.Gray | Brassicaceae | 8 |
| Lepidium bipinnatifidum | Desv. | Brassicaceae | 8 |
| Lepidium densiflorum | Schrad. | Brassicaceae | 8 |
| Lepidium flavum | Torr. | Brassicaceae | 8 |
| Lepidium lasiocarpum | Nutt. | Brassicaceae | 8 |
| Lepidium montanum | Nutt. | Brassicaceae | 8 |
| Lepidium nitidum | Nutt. | Brassicaceae | 8 |
| Lepidium oblongum | Small | Brassicaceae | 8 |
| Lepidium thurberi | Wooton | Brassicaceae | 8 |
| Lepidium virginicum | L. | Brassicaceae | 8 |
| Lepidospartum squamatum | (A.Gray) A.Gray | Asteraceae | 8 |
| Leptochloa crinita | (Lag.) P.M.Peterson & N.Snow | Poaceae | 8 |
| Leptochloa panicea | (Retz.) Ohwi | Poaceae | 8 |
| Leptochloa panicoides | (J.Presl) Hitchc. | Poaceae | 8 |
| Leptosiphon chrysanthus | J.M.Porter & R.Patt. | Polemoniaceae | 8 |
| Leptosiphon floribundus | (A.Gray) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Leptosiphon lemmonii | (A.Gray) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Leptosiphon liniflorus | (Benth.) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Leptosiphon nuttallii | (A.Gray) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Leptosiphon parviflorus | Benth. | Polemoniaceae | 8 |
| Leptosiphon pygmaeus | (Brand) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Leptospron adenanthum | (G.Mey.) A.Delgado | Fabaceae | 8 |
| Lessingia glandulifera | A.Gray | Asteraceae | 8 |
| Leucaena diversifolia | (Schltdl.) Benth. | Fabaceae | 8 |
| Leucophyllum frutescens | (Berland.) I.M.Johnst. | Scrophulariaceae | 8 |
| Leucosyris carnosa | (A.Gray) Greene | Asteraceae | 8 |
| Lewisia brachycalyx | Engelm. ex A.Gray | Montiaceae | 8 |
| Leymus condensatus | (J.Presl) Á.Löve | Poaceae | 8 |
| Leymus triticoides | (Buckley) Pilg. | Poaceae | 8 |
| Libidibia coriaria | (Jacq.) Schltdl. | Fabaceae | 8 |
| Libidibia sclerocarpa | (Standl.) Britton & Rose | Fabaceae | 8 |
| Ligusticum porteri | J.M.Coult. & Rose | Apiaceae | 8 |
| Lilium humboldtii | Leichtlin | Liliaceae | 8 |
| Lilium pardalinum | Kellogg | Liliaceae | 8 |
| Lilium parryi | S.Watson | Liliaceae | 8 |
| Limnocharis flava | (L.) Buchenau | Alismataceae | 8 |
| Limonium californicum | (Boiss.) A.Heller | Plumbaginaceae | 8 |
| Limosella aquatica | L. | Plantaginaceae | 8 |
| Linanthus bellus | (A.Gray) Greene | Polemoniaceae | 8 |
| Linanthus dianthiflorus | (Benth.) Greene | Polemoniaceae | 8 |
| Linanthus dichotomus | Benth. | Polemoniaceae | 8 |
| Linanthus jonesii | (A.Gray) Greene | Polemoniaceae | 8 |
| Linanthus orcuttii | (Parry) Jeps. | Polemoniaceae | 8 |
| Linanthus pungens | (Torr.) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Lindernia dubia | (L.) Pennell | Linderniaceae | 8 |
| Linum aristatum | Engelm. | Linaceae | 8 |
| Linum australe | A.Heller | Linaceae | 8 |
| Linum lewisii | Pursh | Linaceae | 8 |
| Linum micranthum | A.Gray | Linaceae | 8 |
| Linum neomexicanum | Greene | Linaceae | 8 |
| Linum puberulum | (Engelm.) A.Heller | Linaceae | 8 |
| Liparis vexillifera | (Lex.) Cogn. | Orchidaceae | 8 |
| Lippia alba | (Mill.) N.E.Br. ex Britton & P.Wilson | Verbenaceae | 8 |
| Lippia myriocephala | Schltdl. & Cham. | Verbenaceae | 8 |
| Lippia umbellata | Cav. | Verbenaceae | 8 |
| Lithophragma affine | A.Gray | Saxifragaceae | 8 |
| Lithophragma cymbalaria | Torr. & A.Gray | Saxifragaceae | 8 |
| Lithophragma heterophyllum | (Hook. & Arn.) Hook. & Arn. | Saxifragaceae | 8 |
| Lithospermum cobrense | Greene | Boraginaceae | 8 |
| Lithospermum distichum | Ortega | Boraginaceae | 8 |
| Lithospermum exsertum | (D.Don) J.I.Cohen | Boraginaceae | 8 |
| Lithospermum incisum | Lehm. | Boraginaceae | 8 |
| Lithospermum multiflorum | Torr. ex A.Gray | Boraginaceae | 8 |
| Litsea glaucescens | Kunth | Lauraceae | 8 |
| Llavea cordifolia | Lag. | Pteridaceae | 8 |
| Lobelia anatina | E.Wimm. | Campanulaceae | 8 |
| Lobelia cardinalis | L. | Campanulaceae | 8 |
| Lobelia fenestralis | Cav. | Campanulaceae | 8 |
| Lobelia irasuensis | Planch. & Oerst. | Campanulaceae | 8 |
| Lobelia laxiflora | Kunth | Campanulaceae | 8 |
| Loeflingia squarrosa | Nutt. | Caryophyllaceae | 8 |
| Loeselia amplectens | (Hook. & Arn.) Benth. ex DC. | Polemoniaceae | 8 |
| Loeselia ciliata | L. | Polemoniaceae | 8 |
| Loeselia glandulosa | (Cav.) G.Don | Polemoniaceae | 8 |
| Loeselia mexicana | Brand | Polemoniaceae | 8 |
| Loeselia pumila | Walp. | Polemoniaceae | 8 |
| Loeseliastrum matthewsii | (A.Gray) Timbrook | Polemoniaceae | 8 |
| Loeseliastrum schottii | (Torr.) Timbrook | Polemoniaceae | 8 |
| Logfia arizonica | (A.Gray) Holub | Asteraceae | 8 |
| Logfia depressa | (A.Gray) Holub | Asteraceae | 8 |
| Lomatium dasycarpum | (Torr. & A.Gray) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium insulare | (Eastw.) Munz | Apiaceae | 8 |
| Lomatium lucidum | (Nutt.) Jeps. | Apiaceae | 8 |
| Lomatium mohavense | (J.M.Coult. & Rose) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium nevadense | (S.Watson) J.M.Coult. & Rose | Apiaceae | 8 |
| Lonchocarpus parviflorus | Benth. | Fabaceae | 8 |
| Lonicera albiflora | Torr. & A.Gray | Caprifoliaceae | 8 |
| Lonicera involucrata | (Richardson) Banks ex Spreng. | Caprifoliaceae | 8 |
| Lonicera pilosa | Willd. ex Kunth | Caprifoliaceae | 8 |
| Lonicera subspicata | Hook. & Arn. | Caprifoliaceae | 8 |
| Lopezia miniata | DC. | Onagraceae | 8 |
| Lopezia racemosa | Cav. | Onagraceae | 8 |
| Lophocereus schottii | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Ludwigia erecta | (L.) H.Hara | Onagraceae | 8 |
| Ludwigia leptocarpa | (Nutt.) H.Hara | Onagraceae | 8 |
| Ludwigia octovalvis | (Jacq.) P.H.Raven | Onagraceae | 8 |
| Ludwigia palustris | (L.) Elliott | Onagraceae | 8 |
| Ludwigia peploides | (Kunth) P.H.Raven | Onagraceae | 8 |
| Luehea candida | (Moc. & Sessé ex DC.) Mart. | Malvaceae | 8 |
| Lupinus albifrons | Benth. | Fabaceae | 8 |
| Lupinus arboreus | Sims | Fabaceae | 8 |
| Lupinus argenteus | Pursh | Fabaceae | 8 |
| Lupinus arizonicus | (S.Watson) S.Watson | Fabaceae | 8 |
| Lupinus bicolor | Lindl. | Fabaceae | 8 |
| Lupinus brevicaulis | S.Watson | Fabaceae | 8 |
| Lupinus concinnus | J.Agardh | Fabaceae | 8 |
| Lupinus elegans | Kunth | Fabaceae | 8 |
| Lupinus excubitus | M.E.Jones | Fabaceae | 8 |
| Lupinus formosus | Greene | Fabaceae | 8 |
| Lupinus grayi | S.Watson | Fabaceae | 8 |
| Lupinus hirsutissimus | Benth. | Fabaceae | 8 |
| Lupinus hyacinthinus | Greene | Fabaceae | 8 |
| Lupinus latifolius | Lindl. ex J.Agardh | Fabaceae | 8 |
| Lupinus longifolius | (S.Watson) Abrams | Fabaceae | 8 |
| Lupinus microcarpus | Sims | Fabaceae | 8 |
| Lupinus montanus | Kunth | Fabaceae | 8 |
| Lupinus sparsiflorus | Benth. | Fabaceae | 8 |
| Lupinus succulentus | Douglas ex K.Koch | Fabaceae | 8 |
| Lupinus truncatus | Nutt. ex Hook. & Arn. | Fabaceae | 8 |
| Luzula comosa | E.Mey. | Juncaceae | 8 |
| Lycianthes scandens | (Mill.) M.Nee | Solanaceae | 8 |
| Lycium andersonii | A.Gray | Solanaceae | 8 |
| Lycium berlandieri | Dunal | Solanaceae | 8 |
| Lycium brevipes | Benth. | Solanaceae | 8 |
| Lycium californicum | Nutt. ex A.Gray | Solanaceae | 8 |
| Lycium carolinianum | Walter | Solanaceae | 8 |
| Lycium exsertum | A.Gray | Solanaceae | 8 |
| Lycium fremontii | A.Gray | Solanaceae | 8 |
| Lycium pallidum | Miers | Solanaceae | 8 |
| Lycium parishii | A.Gray | Solanaceae | 8 |
| Lycium torreyi | A.Gray | Solanaceae | 8 |
| Lygodium venustum | Sw. | Lygodiaceae | 8 |
| Lyrocarpa coulteri | Hook. & Harv. | Brassicaceae | 8 |
| Lysiloma acapulcense | (Kunth) Benth. | Fabaceae | 8 |
| Lysiloma candidum | Brandegee | Fabaceae | 8 |
| Lysiloma divaricatum | (Jacq.) J.F.Macbr. | Fabaceae | 8 |
| Lysimachia minima | (L.) U.Manns & Anderb. | Primulaceae | 8 |
| Lythrum californicum | Torr. & A.Gray | Lythraceae | 8 |
| Machaeranthera tagetina | Greene | Asteraceae | 8 |
| Machaeranthera tanacetifolia | (Kunth) Nees | Asteraceae | 8 |
| Maclura tinctoria | (L.) D.Don ex G.Don | Moraceae | 8 |
| Macroptilium atropurpureum | (DC.) Urb. | Fabaceae | 8 |
| Macroptilium gibbosifolium | (Ortega) A.Delgado | Fabaceae | 8 |
| Macroptilium lathyroides | (L.) Urb. | Fabaceae | 8 |
| Macroscepis diademata | (Ker Gawl.) W.D.Stevens | Apocynaceae | 8 |
| Madia elegans | D.Don | Asteraceae | 8 |
| Madia exigua | (Sm.) Greene | Asteraceae | 8 |
| Madia gracilis | (Sm.) D.D.Keck & J.C.Clausen ex Applegate | Asteraceae | 8 |
| Malachra alceifolia | Jacq. | Malvaceae | 8 |
| Malacothamnus densiflorus | (S.Watson) Greene | Malvaceae | 8 |
| Malacothamnus enigmaticus | K.Morse & T.Chester | Malvaceae | 8 |
| Malacothamnus fasciculatus | (Nutt. ex Torr. & A.Gray) Greene | Malvaceae | 8 |
| Malacothamnus foliosus | (S.Watson) Kearney | Malvaceae | 8 |
| Malacothrix californica | DC. | Asteraceae | 8 |
| Malacothrix clevelandii | A.Gray | Asteraceae | 8 |
| Malacothrix coulteri | Harv. & A.Gray | Asteraceae | 8 |
| Malacothrix fendleri | A.Gray | Asteraceae | 8 |
| Malacothrix foliosa | A.Gray | Asteraceae | 8 |
| Malacothrix glabrata | (A.Gray ex D.C.Eaton) A.Gray | Asteraceae | 8 |
| Malacothrix stebbinsii | W.S.Davis & P.H.Raven | Asteraceae | 8 |
| Malaxis brachystachys | (Rchb.f.) Kuntze | Orchidaceae | 8 |
| Malaxis macrostachya | (Lex.) Kuntze | Orchidaceae | 8 |
| Malaxis unifolia | Michx. | Orchidaceae | 8 |
| Malosma laurina | (Nutt.) Nutt. ex Abrams | Anacardiaceae | 8 |
| Malperia tenuis | S.Watson | Asteraceae | 8 |
| Malpighia diversifolia | Brandegee | Malpighiaceae | 8 |
| Malpighia emarginata | DC. | Malpighiaceae | 8 |
| Malpighia glabra | L. | Malpighiaceae | 8 |
| Malva pacifica | M.F.Ray | Malvaceae | 8 |
| Malvastrum americanum | (L.) Torr. | Malvaceae | 8 |
| Malvastrum coromandelianum | (L.) Garcke | Malvaceae | 8 |
| Malvaviscus arboreus | Dill. ex Cav. | Malvaceae | 8 |
| Malvella lepidota | (A.Gray) Fryxell | Malvaceae | 8 |
| Malvella leprosa | (Ortega) Krapov. | Malvaceae | 8 |
| Malvella sagittifolia | (A.Gray) Fryxell | Malvaceae | 8 |
| Mammillaria beneckei | Ehrenb. | Cactaceae | 8 |
| Mammillaria brandegeei | (J.M.Coult.) K.Brandegee | Cactaceae | 8 |
| Mammillaria heyderi | Muehlenpf. | Cactaceae | 8 |
| Mammillaria lasiacantha | Engelm. | Cactaceae | 8 |
| Mammillaria petrophila | K.Brandegee | Cactaceae | 8 |
| Mammillaria scrippsiana | (Britton & Rose) Orcutt | Cactaceae | 8 |
| Mammillaria senilis | Lodd. ex Salm-Dyck | Cactaceae | 8 |
| Mandevilla foliosa | (Müll.Arg.) Hemsl. | Apocynaceae | 8 |
| Mandevilla hypoleuca | (Benth.) Pichon | Apocynaceae | 8 |
| Mandevilla subsagittata | (Ruiz & Pav.) Woodson | Apocynaceae | 8 |
| Mandevilla tubiflora | (M.Martens & Galeotti) Woodson | Apocynaceae | 8 |
| Manihot angustiloba | (Torr.) Müll.Arg. | Euphorbiaceae | 8 |
| Manilkara zapota | (L.) P.Royen | Sapotaceae | 8 |
| Marah gilensis | (Greene) Greene | Cucurbitaceae | 8 |
| Marah macrocarpa | (Greene) Greene | Cucurbitaceae | 8 |
| Maranta arundinacea | L. | Marantaceae | 8 |
| Margaritaria nobilis | L.f. | Phyllanthaceae | 8 |
| Marina calycosa | (A.Gray) Barneby | Fabaceae | 8 |
| Marina divaricata | (Benth.) Barneby | Fabaceae | 8 |
| Marina maritima | (Brandegee) Barneby | Fabaceae | 8 |
| Marina parryi | (Torr. & A.Gray) Barneby | Fabaceae | 8 |
| Marsilea vestita | Hook. & Grev. | Marsileaceae | 8 |
| Martynia annua | L. | Martyniaceae | 8 |
| Maurandella antirrhiniflora | (Humb. & Bonpl. ex Willd.) Rothm. | Plantaginaceae | 8 |
| Maxillaria variabilis | Bateman ex Lindl. | Orchidaceae | 8 |
| Mayaca fluviatilis | Aubl. | Mayacaceae | 8 |
| Maytenus phyllanthoides | Benth. | Celastraceae | 8 |
| Mecardonia procumbens | (Mill.) Small | Plantaginaceae | 8 |
| Mecardonia vandellioides | (Kunth) Pennell | Plantaginaceae | 8 |
| Meconella denticulata | Greene | Papaveraceae | 8 |
| Melampodium cinereum | DC. | Asteraceae | 8 |
| Melampodium divaricatum | DC. | Asteraceae | 8 |
| Melampodium gracile | Less. | Asteraceae | 8 |
| Melampodium leucanthum | Torr. & A.Gray | Asteraceae | 8 |
| Melampodium perfoliatum | (Cav.) Kunth | Asteraceae | 8 |
| Melampodium sericeum | Lag. | Asteraceae | 8 |
| Melampodium sinuatum | Brandegee | Asteraceae | 8 |
| Melampodium strigosum | Stuessy | Asteraceae | 8 |
| Melica frutescens | Scribn. | Poaceae | 8 |
| Melica imperfecta | Trin. | Poaceae | 8 |
| Meliosma dentata | (Liebm.) Urb. | Sabiaceae | 8 |
| Melochia nodiflora | Sw. | Malvaceae | 8 |
| Melochia pyramidata | L. | Malvaceae | 8 |
| Melochia tomentosa | L. | Malvaceae | 8 |
| Melothria pendula | L. | Cucurbitaceae | 8 |
| Melothria scabra | Naudin | Cucurbitaceae | 8 |
| Menodora scabra | Engelm. ex A.Gray | Oleaceae | 8 |
| Menodora spinescens | A.Gray | Oleaceae | 8 |
| Mentha canadensis | L. | Lamiaceae | 8 |
| Mentzelia adhaerens | Benth. | Loasaceae | 8 |
| Mentzelia affinis | Greene | Loasaceae | 8 |
| Mentzelia albicaulis | (Douglas ex Hook.) Douglas ex Torr. & A.Gray | Loasaceae | 8 |
| Mentzelia aspera | L. | Loasaceae | 8 |
| Mentzelia dispersa | S.Watson | Loasaceae | 8 |
| Mentzelia hirsutissima | S.Watson | Loasaceae | 8 |
| Mentzelia hispida | Willd. | Loasaceae | 8 |
| Mentzelia involucrata | S.Watson | Loasaceae | 8 |
| Mentzelia longiloba | J.Darl. | Loasaceae | 8 |
| Mentzelia micrantha | (Hook. & Arn.) Torr. & A.Gray | Loasaceae | 8 |
| Mentzelia montana | (Davidson) Davidson | Loasaceae | 8 |
| Mentzelia procera | (Wooton & Standl.) J.J.Schenk & L.Hufford | Loasaceae | 8 |
| Mentzelia puberula | J.Darl. | Loasaceae | 8 |
| Mentzelia texana | Urb. & Gilg | Loasaceae | 8 |
| Mentzelia veatchiana | Kellogg | Loasaceae | 8 |
| Mesadenus lucayanus | (Britton) Schltr. | Orchidaceae | 8 |
| Mesosphaerum oblongifolium | (Benth.) Kuntze | Lamiaceae | 8 |
| Mesosphaerum urticodes | (Kunth) Kuntze | Lamiaceae | 8 |
| Mespilodaphne veraguensis | (Meisn.) Rohwer | Lauraceae | 8 |
| Metastelma arizonicum | A.Gray | Apocynaceae | 8 |
| Miconia glaberrima | (Schltdl.) Naudin | Melastomataceae | 8 |
| Miconia petiolaris | (Schltdl.) Michelang. | Melastomataceae | 8 |
| Miconia xalapensis | (Bonpl.) M.Gómez | Melastomataceae | 8 |
| Micranthes californica | (Greene) Small | Saxifragaceae | 8 |
| Microlobius foetidus | (Jacq.) M.Sousa & G.Andrade | Fabaceae | 8 |
| Micropus californicus | Fisch. & C.A.Mey. | Asteraceae | 8 |
| Microseris douglasii | (DC.) Sch.Bip. | Asteraceae | 8 |
| Microstachys corniculata | (Vahl) A.Juss. ex Griseb. | Euphorbiaceae | 8 |
| Microsteris gracilis | (Hook.) Greene | Polemoniaceae | 8 |
| Mikania cordifolia | (L.f.) Willd. | Asteraceae | 8 |
| Mikania micrantha | Kunth | Asteraceae | 8 |
| Milla biflora | Cav. | Asparagaceae | 8 |
| Milleria quinqueflora | L. | Asteraceae | 8 |
| Mimetanthe pilosa | (Benth.) Greene | Phrymaceae | 8 |
| Mimosa aculeaticarpa | Ortega | Fabaceae | 8 |
| Mimosa albida | Humb. & Bonpl. ex Willd. | Fabaceae | 8 |
| Mimosa berlandieri | A.Gray | Fabaceae | 8 |
| Mimosa biuncifera | Benth. | Fabaceae | 8 |
| Mimosa diplotricha | C.Wright | Fabaceae | 8 |
| Mimosa distachya | Cav. | Fabaceae | 8 |
| Mimosa dysocarpa | Benth. | Fabaceae | 8 |
| Mimosa grahamii | A.Gray | Fabaceae | 8 |
| Mimosa pigra | L. | Fabaceae | 8 |
| Mimosa quadrivalvis | L. | Fabaceae | 8 |
| Mimosa spirocarpa | Rose | Fabaceae | 8 |
| Mimosa texana | (A.Gray) Small | Fabaceae | 8 |
| Mimosa tricephala | Schltdl. & Cham. | Fabaceae | 8 |
| Mirabilis albida | (Walter) Heimerl | Nyctaginaceae | 8 |
| Mirabilis coccinea | (Torr.) Benth. & Hook.f. | Nyctaginaceae | 8 |
| Mirabilis jalapa | L. | Nyctaginaceae | 8 |
| Mirabilis laevis | (Benth.) Curran | Nyctaginaceae | 8 |
| Mirabilis linearis | (Pursh) Heimerl | Nyctaginaceae | 8 |
| Mirabilis longiflora | L. | Nyctaginaceae | 8 |
| Mirabilis multiflora | (Torr.) A.Gray | Nyctaginaceae | 8 |
| Mirabilis tenuiloba | S.Watson | Nyctaginaceae | 8 |
| Mitracarpus hirtus | (L.) DC. | Rubiaceae | 8 |
| Mitreola petiolata | (J.F.Gmel.) Torr. & A.Gray | Loganiaceae | 8 |
| Mohavea confertiflora | (Benth.) Jeps. | Plantaginaceae | 8 |
| Mollugo verticillata | L. | Molluginaceae | 8 |
| Monarda citriodora | Cerv. ex Lag. | Lamiaceae | 8 |
| Monardella breweri | A.Gray | Lamiaceae | 8 |
| Monardella macrantha | A.Gray | Lamiaceae | 8 |
| Monardella nana | A.Gray | Lamiaceae | 8 |
| Monnina ciliolata | Moc. & Sessé ex DC. | Polygalaceae | 8 |
| Monnina wrightii | A.Gray | Polygalaceae | 8 |
| Monnina xalapensis | Kunth | Polygalaceae | 8 |
| Monochaetum floribundum | Naudin | Melastomataceae | 8 |
| Monoptilon bellioides | H.M.Hall | Asteraceae | 8 |
| Monotropa uniflora | L. | Ericaceae | 8 |
| Montanoa bipinnatifida | (Kunth) K.Koch | Asteraceae | 8 |
| Montanoa leucantha | (Lag.) S.F.Blake | Asteraceae | 8 |
| Montanoa tomentosa | Cerv. | Asteraceae | 8 |
| Montia fontana | L. | Montiaceae | 8 |
| Morisonia americana | L. | Capparaceae | 8 |
| Morisonia atamisquea | (Kuntze) Christenh. & Byng | Capparaceae | 8 |
| Morisonia flexuosa | L. | Capparaceae | 8 |
| Morisonia indica | (L.) ined. | Capparaceae | 8 |
| Mortonia greggii | A.Gray | Celastraceae | 8 |
| Mortonia scabrella | A.Gray | Celastraceae | 8 |
| Morus celtidifolia | Kunth | Moraceae | 8 |
| Morus microphylla | Buckley | Moraceae | 8 |
| Muhlenbergia alopecuroides | (Griseb.) P.M.Peterson & Columbus | Poaceae | 8 |
| Muhlenbergia arenacea | (Buckley) Hitchc. | Poaceae | 8 |
| Muhlenbergia arenicola | Buckley | Poaceae | 8 |
| Muhlenbergia asperifolia | (Nees & Meyen ex Trin.) Parodi | Poaceae | 8 |
| Muhlenbergia emersleyi | Vasey | Poaceae | 8 |
| Muhlenbergia longiligula | Hitchc. | Poaceae | 8 |
| Muhlenbergia microsperma | Trin. | Poaceae | 8 |
| Muhlenbergia minutissima | (Steud.) Swallen | Poaceae | 8 |
| Muhlenbergia montana | (Nutt.) Hitchc. | Poaceae | 8 |
| Muhlenbergia phalaroides | (Kunth) P.M.Peterson | Poaceae | 8 |
| Muhlenbergia porteri | Scribn. | Poaceae | 8 |
| Muhlenbergia richardsonis | (Trin.) Rydb. | Poaceae | 8 |
| Muhlenbergia rigens | (Benth.) Hitchc. | Poaceae | 8 |
| Muhlenbergia rigida | (Kunth) Kunth | Poaceae | 8 |
| Muhlenbergia sinuosa | Swallen | Poaceae | 8 |
| Muhlenbergia torreyi | (Kunth) Hitchc. ex Bush | Poaceae | 8 |
| Muhlenbergia tricholepis | (Torr.) P.M.Peterson | Poaceae | 8 |
| Muhlenbergia utilis | (Torr.) Hitchc. | Poaceae | 8 |
| Muhlenbergia wrightii | Vasey ex J.M.Coult. | Poaceae | 8 |
| Munroa pulchella | (Kunth) Amarilla | Poaceae | 8 |
| Myrcia chytraculia | (L.) A.R.Lourenço & E.Lucas | Myrtaceae | 8 |
| Myrcianthes fragrans | (Sw.) McVaugh | Myrtaceae | 8 |
| Myriopteris alabamensis | (Buckley) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris aurea | (Poir.) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris clevelandii | (D.C.Eaton) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris covillei | (Maxon) Á.Löve & D.Löve | Pteridaceae | 8 |
| Myriopteris fendleri | Fourn. | Pteridaceae | 8 |
| Myriopteris lendigera | (Cav.) J.Sm. | Pteridaceae | 8 |
| Myriopteris lindheimeri | J.Sm. | Pteridaceae | 8 |
| Myriopteris microphylla | (Sw.) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris myriophylla | J.Sm. | Pteridaceae | 8 |
| Myriopteris newberryi | (D.C.Eaton) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris parryi | (D.C.Eaton) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris rufa | Fée | Pteridaceae | 8 |
| Myriopteris tomentosa | (Link) Fée | Pteridaceae | 8 |
| Myriopteris viscida | (Davenp.) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris windhamii | Grusz | Pteridaceae | 8 |
| Myriopteris wootonii | (Maxon) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris wrightii | (Hook.) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris yavapensis | (T.Reeves ex Windham) Grusz & Windham | Pteridaceae | 8 |
| Myriopus volubilis | (L.) Small | Heliotropiaceae | 8 |
| Myrsine coriacea | (Sw.) R.Br. ex Roem. & Schult. | Primulaceae | 8 |
| Myrtillocactus cochal | (Orcutt) Britton & Rose | Cactaceae | 8 |
| Myrtillocactus geometrizans | (Mart. ex Pfeiff.) Console | Cactaceae | 8 |
| Najas flexilis | (Willd.) Rostk. & W.L.E.Schmidt | Hydrocharitaceae | 8 |
| Najas guadalupensis | (Spreng.) Magnus | Hydrocharitaceae | 8 |
| Najas marina | L. | Hydrocharitaceae | 8 |
| Nama demissa | A.Gray | Namaceae | 8 |
| Nama dichotoma | (Ruiz & Pav.) Choisy | Namaceae | 8 |
| Nama hispida | A.Gray | Namaceae | 8 |
| Nama jamaicensis | L. | Namaceae | 8 |
| Nama stenocarpa | A.Gray | Namaceae | 8 |
| Nanogalactia brachystachys | (Benth.) L.P.Queiroz | Fabaceae | 8 |
| Nassella lepida | (Hitchc.) Barkworth | Poaceae | 8 |
| Nassella pulchra | (Hitchc.) Barkworth | Poaceae | 8 |
| Navarretia atractyloides | Hook. & Arn. | Polemoniaceae | 8 |
| Navarretia fossalis | Moran | Polemoniaceae | 8 |
| Navarretia hamata | Greene | Polemoniaceae | 8 |
| Navarretia intertexta | Hook. | Polemoniaceae | 8 |
| Navarretia peninsularis | Greene | Polemoniaceae | 8 |
| Neea psychotrioides | Donn.Sm. | Nyctaginaceae | 8 |
| Neltuma articulata | (S.Watson) Britton & Rose | Fabaceae | 8 |
| Neltuma glandulosa | (Torr.) Britton & Rose | Fabaceae | 8 |
| Neltuma juliflora | (Sw.) Raf. | Fabaceae | 8 |
| Neltuma odorata | (Torr. & Frém.) C.E.Hughes & G.P.Lewis | Fabaceae | 8 |
| Neltuma velutina | (Wooton) Britton & Rose | Fabaceae | 8 |
| Neltuma yaquiana | (R.A.Palacios) C.E.Hughes & G.P.Lewis | Fabaceae | 8 |
| Nemacaulis denudata | Nutt. | Polygonaceae | 8 |
| Nemacladus glanduliferus | Jeps. | Campanulaceae | 8 |
| Nemacladus orientalis | (McVaugh) Morin | Campanulaceae | 8 |
| Nemacladus pinnatifidus | Greene | Campanulaceae | 8 |
| Nemacladus ramosissimus | Nutt. | Campanulaceae | 8 |
| Nemacladus rubescens | Greene | Campanulaceae | 8 |
| Nemacladus sigmoideus | G.T.Robbins | Campanulaceae | 8 |
| Nemophila menziesii | Hook. & Arn. | Hydrophyllaceae | 8 |
| Nemophila pedunculata | Douglas ex Benth. | Hydrophyllaceae | 8 |
| Neogaerrhinum filipes | (A.Gray) Rothm. | Plantaginaceae | 8 |
| Neogaerrhinum strictum | (Hook. & Arn.) Rothm. | Plantaginaceae | 8 |
| Nephroia diversifolia | (DC.) L.Lian & Wei Wang | Menispermaceae | 8 |
| Neptunia oleracea | Lour. | Fabaceae | 8 |
| Neptunia plena | (L.) Benth. | Fabaceae | 8 |
| Nicolletia occidentalis | A.Gray | Asteraceae | 8 |
| Nicolletia trifida | Rydb. | Asteraceae | 8 |
| Nicotiana attenuata | Torr. ex S.Watson | Solanaceae | 8 |
| Nicotiana clevelandii | A.Gray | Solanaceae | 8 |
| Nicotiana obtusifolia | M.Martens & Galeotti | Solanaceae | 8 |
| Nicotiana plumbaginifolia | Viv. | Solanaceae | 8 |
| Nissolia fruticosa | Jacq. | Fabaceae | 8 |
| Nissolia microptera | Poir. | Fabaceae | 8 |
| Nissolia pringlei | Rose | Fabaceae | 8 |
| Nissolia schottii | A.Gray | Fabaceae | 8 |
| Nitrophila occidentalis | (Moq.) S.Watson | Chenopodiaceae | 8 |
| Noccaea fendleri | (A.Gray) Holub | Brassicaceae | 8 |
| Nolina bigelovii | (Torr.) S.Watson | Asparagaceae | 8 |
| Nolina interrata | Gentry | Asparagaceae | 8 |
| Nolina microcarpa | S.Watson | Asparagaceae | 8 |
| Nolina parryi | S.Watson | Asparagaceae | 8 |
| Nolina texana | S.Watson | Asparagaceae | 8 |
| Notholaena aschenborniana | Klotzsch | Pteridaceae | 8 |
| Notholaena brachypus | (Kunze) J.Sm. | Pteridaceae | 8 |
| Notholaena candida | (M.Martens & Galeotti) Hook. | Pteridaceae | 8 |
| Notholaena lemmonii | D.C.Eaton | Pteridaceae | 8 |
| Nothoscordum bivalve | (L.) Britton | Amaryllidaceae | 8 |
| Nuttallanthus canadensis | (L.) D.A.Sutton | Plantaginaceae | 8 |
| Nuttallanthus texanus | (Scheele) D.A.Sutton | Plantaginaceae | 8 |
| Nyctocereus serpentinus | (Lag. & Rodr.) Britton & Rose | Cactaceae | 8 |
| Nymphaea ampla | (Salisb.) DC. | Nymphaeaceae | 8 |
| Nymphaea elegans | Hook. | Nymphaeaceae | 8 |
| Ocimum campechianum | Mill. | Lamiaceae | 8 |
| Odontonema callistachyum | (Schltdl. & Cham.) Kuntze | Acanthaceae | 8 |
| Odontostephana reticulata | (Engelm. ex A.Gray) Morillo, Liede & Meve | Apocynaceae | 8 |
| Oenothera albicaulis | Nutt. ex Pursh | Onagraceae | 8 |
| Oenothera avita | (W.M.Klein) W.M.Klein | Onagraceae | 8 |
| Oenothera brachycarpa | A.Gray | Onagraceae | 8 |
| Oenothera cespitosa | Nutt. | Onagraceae | 8 |
| Oenothera curtiflora | W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera deltoides | Torr. & Frém. | Onagraceae | 8 |
| Oenothera deserticola | (Loes.) Munz | Onagraceae | 8 |
| Oenothera drummondii | Hook. | Onagraceae | 8 |
| Oenothera elata | Kunth | Onagraceae | 8 |
| Oenothera flava | (A.Nelson) Garrett | Onagraceae | 8 |
| Oenothera hartwegii | Benth. | Onagraceae | 8 |
| Oenothera hexandra | (Ortega) W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera kunthiana | (Spach) Munz | Onagraceae | 8 |
| Oenothera laciniata | Hill | Onagraceae | 8 |
| Oenothera pallida | Lindl. | Onagraceae | 8 |
| Oenothera podocarpa | (Wooton & Standl.) Krakos & W.L.Wagner | Onagraceae | 8 |
| Oenothera primiveris | A.Gray | Onagraceae | 8 |
| Oenothera pubescens | Wild. ex Spreng. | Onagraceae | 8 |
| Oenothera rosea | Aiton | Onagraceae | 8 |
| Oenothera speciosa | Nutt. | Onagraceae | 8 |
| Oenothera suffrutescens | (Ser.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera tetraptera | Cav. | Onagraceae | 8 |
| Oenothera toumeyi | (Small) Tidestr. | Onagraceae | 8 |
| Oenothera triloba | Nutt. | Onagraceae | 8 |
| Oenothera wigginsii | W.M.Klein | Onagraceae | 8 |
| Okenia hypogaea | Schltdl. & Cham. | Nyctaginaceae | 8 |
| Oligomeris linifolia | (Vahl ex Hornem.) J.F.Macbr. | Resedaceae | 8 |
| Olneya tesota | A.Gray | Fabaceae | 8 |
| Oncidium graminifolium | (Lindl.) Lindl. | Orchidaceae | 8 |
| Operculina pinnatifida | (Kunth) O'Donell | Convolvulaceae | 8 |
| Operculina pteripes | (G.Don) O'Donell | Convolvulaceae | 8 |
| Ophioglossum californicum | Prantl | Ophioglossaceae | 8 |
| Ophioglossum crotalophoroides | Walter | Ophioglossaceae | 8 |
| Ophioglossum engelmannii | Prantl | Ophioglossaceae | 8 |
| Ophioglossum polyphyllum | A.Braun ex Seub. | Ophioglossaceae | 8 |
| Ophioglossum vulgatum | L. | Ophioglossaceae | 8 |
| Oplismenus compositus | (L.) P.Beauv. | Poaceae | 8 |
| Oplismenus hirtellus | (L.) P.Beauv. | Poaceae | 8 |
| Opuntia basilaris | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Opuntia bravoana | Baxter | Cactaceae | 8 |
| Opuntia chlorotica | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Opuntia comonduensis | (J.M.Coult.) Britton & Rose | Cactaceae | 8 |
| Opuntia decumbens | Salm-Dyck | Cactaceae | 8 |
| Opuntia engelmannii | Salm-Dyck ex Engelm. | Cactaceae | 8 |
| Opuntia excelsa | Sánchez-Mej. | Cactaceae | 8 |
| Opuntia gosseliniana | F.A.C.Weber | Cactaceae | 8 |
| Opuntia leucotricha | DC. | Cactaceae | 8 |
| Opuntia littoralis | (Engelm.) Cockerell | Cactaceae | 8 |
| Opuntia macrocentra | Engelm. | Cactaceae | 8 |
| Opuntia macrorhiza | Engelm. | Cactaceae | 8 |
| Opuntia microdasys | (Lehm.) Pfeiff. | Cactaceae | 8 |
| Opuntia orbiculata | Salm-Dyck ex Pfeiff. | Cactaceae | 8 |
| Opuntia oricola | Philbrick | Cactaceae | 8 |
| Opuntia phaeacantha | Engelm. | Cactaceae | 8 |
| Opuntia polyacantha | Haw. | Cactaceae | 8 |
| Opuntia puberula | Pfeiff. | Cactaceae | 8 |
| Opuntia pubescens | H.L.Wendl. ex Pfeiff. | Cactaceae | 8 |
| Opuntia pycnantha | Engelm. | Cactaceae | 8 |
| Opuntia robusta | Pfeiff. | Cactaceae | 8 |
| Opuntia tomentosa | Salm-Dyck | Cactaceae | 8 |
| Orcuttia californica | Vasey | Poaceae | 8 |
| Oreocarya suffruticosa | (Torr.) Greene | Boraginaceae | 8 |
| Oreochrysum parryi | Rydb. | Asteraceae | 8 |
| Oreopanax peltatus | Linden ex Regel | Araliaceae | 8 |
| Ornithostaphylos oppositifolia | (Parry) Small | Ericaceae | 8 |
| Orobanche bulbosa | Beck | Orobanchaceae | 8 |
| Orobanche californica | Cham. & Schltdl. | Orobanchaceae | 8 |
| Orobanche cooperi | (A.Gray) A.Heller | Orobanchaceae | 8 |
| Orobanche fasciculata | Nutt. | Orobanchaceae | 8 |
| Orobanche ludoviciana | Nutt. | Orobanchaceae | 8 |
| Orthilia secunda | (L.) House | Ericaceae | 8 |
| Osmadenia tenella | Nutt. | Asteraceae | 8 |
| Otatea acuminata | (Munro) C.E.Calderón ex Soderstr. | Poaceae | 8 |
| Oxalis alpina | (Rose) Rose ex R.Knuth | Oxalidaceae | 8 |
| Oxalis caerulea | (Small) R.Knuth | Oxalidaceae | 8 |
| Oxalis californica | (Abrams) R.Knuth | Oxalidaceae | 8 |
| Oxalis decaphylla | Kunth | Oxalidaceae | 8 |
| Oxalis drummondii | A.Gray | Oxalidaceae | 8 |
| Oxalis frutescens | L. | Oxalidaceae | 8 |
| Oxalis latifolia | Kunth | Oxalidaceae | 8 |
| Oxalis pilosa | Nutt. | Oxalidaceae | 8 |
| Oxalis stricta | L. | Oxalidaceae | 8 |
| Oxalis violacea | L. | Oxalidaceae | 8 |
| Oxybaphus nyctagineus | (Michx.) Sweet | Nyctaginaceae | 8 |
| Pachira aquatica | Aubl. | Malvaceae | 8 |
| Pachycereus pecten-aboriginum | (Engelm. ex S.Watson) Britton & Rose | Cactaceae | 8 |
| Pachycereus pringlei | (S.Watson) Britton & Rose | Cactaceae | 8 |
| Pachycormus discolor | (Benth.) Coville | Anacardiaceae | 8 |
| Pachyrhizus erosus | (L.) Urb. | Fabaceae | 8 |
| Packera neomexicana | (A.Gray) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Paeonia californica | Nutt. | Paeoniaceae | 8 |
| Palafoxia arida | B.L.Turner & M.I.Morris | Asteraceae | 8 |
| Palafoxia linearis | Lag. | Asteraceae | 8 |
| Palafoxia sphacelata | (Nutt. ex Torr.) Cory | Asteraceae | 8 |
| Palmerella debilis | A.Gray | Campanulaceae | 8 |
| Panicum capillare | L. | Poaceae | 8 |
| Panicum dichotomiflorum | Michx. | Poaceae | 8 |
| Panicum hirticaule | J.Presl | Poaceae | 8 |
| Panicum virgatum | L. | Poaceae | 8 |
| Pappophorum mucronulatum | Nees | Poaceae | 8 |
| Pappophorum philippianum | Parodi | Poaceae | 8 |
| Pappostipa speciosa | (Trin. & Rupr.) Romasch. | Poaceae | 8 |
| Parietaria floridana | Nutt. | Urticaceae | 8 |
| Parietaria hespera | Hinton | Urticaceae | 8 |
| Parietaria pensylvanica | Muhl. ex Willd. | Urticaceae | 8 |
| Parkinsonia aculeata | L. | Fabaceae | 8 |
| Parkinsonia florida | (Benth. ex A.Gray) S.Watson | Fabaceae | 8 |
| Parkinsonia microphylla | Torr. | Fabaceae | 8 |
| Parkinsonia praecox | (Ruiz & Pav.) Hawkins | Fabaceae | 8 |
| Paronychia jamesii | Torr. & A.Gray | Caryophyllaceae | 8 |
| Parthenium confertum | A.Gray | Asteraceae | 8 |
| Parthenium hysterophorus | L. | Asteraceae | 8 |
| Parthenium incanum | Kunth | Asteraceae | 8 |
| Parthenocissus quinquefolia | (L.) Planch. | Vitaceae | 8 |
| Paspalum denticulatum | Trin. | Poaceae | 8 |
| Paspalum distichum | L. | Poaceae | 8 |
| Paspalum langei | (E.Fourn.) Nash | Poaceae | 8 |
| Paspalum paniculatum | L. | Poaceae | 8 |
| Paspalum pubiflorum | Rupr. ex E.Fourn. | Poaceae | 8 |
| Paspalum vaginatum | Sw. | Poaceae | 8 |
| Passiflora arida | (Mast. & Rose) Killip | Passifloraceae | 8 |
| Passiflora arizonica | (Killip) D.H.Goldman | Passifloraceae | 8 |
| Passiflora biflora | Lam. | Passifloraceae | 8 |
| Passiflora bryonioides | Kunth | Passifloraceae | 8 |
| Passiflora filipes | Benth. | Passifloraceae | 8 |
| Passiflora holosericea | L. | Passifloraceae | 8 |
| Passiflora mexicana | Juss. | Passifloraceae | 8 |
| Passiflora palmeri | Rose | Passifloraceae | 8 |
| Passiflora pentaschista | (Killip) H.T.Svoboda | Passifloraceae | 8 |
| Passiflora porphyretica | Mast. | Passifloraceae | 8 |
| Passiflora sexocellata | Schltdl. | Passifloraceae | 8 |
| Passiflora suberosa | L. | Passifloraceae | 8 |
| Paullinia fuscescens | Kunth | Sapindaceae | 8 |
| Paxistima myrsinites | (Pursh) Raf. | Celastraceae | 8 |
| Pectis cylindrica | Rydb. | Asteraceae | 8 |
| Pectis filipes | Harv. & Gray | Asteraceae | 8 |
| Pectis multiflosculosa | (DC.) Sch.Bip. | Asteraceae | 8 |
| Pectis multiseta | Benth. | Asteraceae | 8 |
| Pectis papposa | Harv. & Gray | Asteraceae | 8 |
| Pectis prostrata | Cav. | Asteraceae | 8 |
| Pectocarya anisocarpa | Veno | Boraginaceae | 8 |
| Pectocarya heterocarpa | (I.M.Johnst.) I.M.Johnst. | Boraginaceae | 8 |
| Pectocarya linearis | (Ruiz & Pav.) DC. | Boraginaceae | 8 |
| Pectocarya penicillata | (Hook. & Arn.) A.DC. | Boraginaceae | 8 |
| Pectocarya platycarpa | (Munz & I.M.Johnst.) Munz & I.M.Johnst. | Boraginaceae | 8 |
| Pectocarya recurvata | I.M.Johnst. | Boraginaceae | 8 |
| Pectocarya setosa | A.Gray | Boraginaceae | 8 |
| Pedicularis densiflora | Benth. | Orobanchaceae | 8 |
| Pediomelum californicum | (S.Watson) Rydb. | Fabaceae | 8 |
| Pediomelum pentaphyllum | (L.) Rydb. | Fabaceae | 8 |
| Pediomelum rhombifolium | (Torr. & A.Gray) Rydb. | Fabaceae | 8 |
| Pediomelum tenuiflorum | (Pursh) A.N.Egan | Fabaceae | 8 |
| Peganum mexicanum | A.Gray | Nitrariaceae | 8 |
| Pelazoneuron puberulum | (Baker) A.R.Sm. & S.E.Fawc. | Thelypteridaceae | 8 |
| Pelecyphora tuberculosa | (Engelm.) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pelecyphora vivipara | (Nutt.) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pellaea andromedifolia | (Kaulf.) Fée | Pteridaceae | 8 |
| Pellaea atropurpurea | (L.) Link | Pteridaceae | 8 |
| Pellaea intermedia | Mett. | Pteridaceae | 8 |
| Pellaea mucronata | D.C.Eaton | Pteridaceae | 8 |
| Pellaea ovata | Weath. | Pteridaceae | 8 |
| Pellaea ternifolia | (Cav.) Link | Pteridaceae | 8 |
| Pellaea truncata | Goodd. | Pteridaceae | 8 |
| Pellaea wrightiana | Hook. | Pteridaceae | 8 |
| Peniocereus greggii | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Peniocereus striatus | (Brandegee) Buxb. | Cactaceae | 8 |
| Pennellia longifolia | (Benth.) Rollins | Brassicaceae | 8 |
| Pennellia micrantha | (A.Gray) Nieuwl. | Brassicaceae | 8 |
| Penstemon barbatus | (Cav.) Roth | Plantaginaceae | 8 |
| Penstemon californicus | (Munz & I.M.Johnst.) D.D.Keck | Plantaginaceae | 8 |
| Penstemon campanulatus | (Cav.) Willd. | Plantaginaceae | 8 |
| Penstemon centranthifolius | (Benth.) Benth. | Plantaginaceae | 8 |
| Penstemon cerrosensis | Kellogg | Plantaginaceae | 8 |
| Penstemon clevelandii | A.Gray | Plantaginaceae | 8 |
| Penstemon dasyphyllus | A.Gray | Plantaginaceae | 8 |
| Penstemon labrosus | (A.Gray) Mast. ex Hook.f. | Plantaginaceae | 8 |
| Penstemon lanceolatus | Benth. | Plantaginaceae | 8 |
| Penstemon leonensis | Straw | Plantaginaceae | 8 |
| Penstemon linarioides | A.Gray | Plantaginaceae | 8 |
| Penstemon pinifolius | Greene | Plantaginaceae | 8 |
| Penstemon pseudospectabilis | M.E.Jones | Plantaginaceae | 8 |
| Penstemon roseus | (Cerv. ex Sweet) G.Don | Plantaginaceae | 8 |
| Penstemon rostriflorus | Kellogg | Plantaginaceae | 8 |
| Penstemon secundiflorus | Benth. | Plantaginaceae | 8 |
| Penstemon spectabilis | Thurb. ex A.Gray | Plantaginaceae | 8 |
| Penstemon superbus | A.Nelson | Plantaginaceae | 8 |
| Penstemon thurberi | Torr. | Plantaginaceae | 8 |
| Pentachaeta aurea | Nutt. | Asteraceae | 8 |
| Pentagramma glanduloviscida | Schuettp. & Windham | Pteridaceae | 8 |
| Pentagramma triangularis | (Kaulf.) Yatsk., Windham & E.Wollenw. | Pteridaceae | 8 |
| Pentagramma viscosa | Schuettp. & Windham | Pteridaceae | 8 |
| Peperomia bracteata | A.W.Hill | Piperaceae | 8 |
| Peperomia galioides | Kunth | Piperaceae | 8 |
| Peperomia obtusifolia | (L.) A.Dietr. | Piperaceae | 8 |
| Peperomia pellucida | (L.) Kunth | Piperaceae | 8 |
| Peperomia quadrifolia | (L.) Kunth | Piperaceae | 8 |
| Peperomia tetraphylla | (G.Forst.) Hook. & Arn. | Piperaceae | 8 |
| Pereskiopsis porteri | (K.Brandegee ex F.A.C.Weber) Britton & Rose | Cactaceae | 8 |
| Pericome caudata | A.Gray | Asteraceae | 8 |
| Periptera punicea | (Lag.) DC. | Malvaceae | 8 |
| Perityle californica | Benth. | Asteraceae | 8 |
| Perityle crassifolia | Brandegee | Asteraceae | 8 |
| Perityle cuneata | Brandegee | Asteraceae | 8 |
| Perityle emoryi | Torr. | Asteraceae | 8 |
| Perityle microglossa | Benth. | Asteraceae | 8 |
| Persicaria amphibia | (L.) Delarbre | Polygonaceae | 8 |
| Persicaria glabra | (Willd.) M.Gómez | Polygonaceae | 8 |
| Persicaria hydropiperoides | (Michx.) Small | Polygonaceae | 8 |
| Persicaria pensylvanica | (L.) M.Gómez | Polygonaceae | 8 |
| Persicaria punctata | Small | Polygonaceae | 8 |
| Perymenium buphthalmoides | DC. | Asteraceae | 8 |
| Perymenium mendezii | DC. | Asteraceae | 8 |
| Petalonyx linearis | Greene | Loasaceae | 8 |
| Petalonyx thurberi | A.Gray | Loasaceae | 8 |
| Petiveria alliacea | L. | Petiveriaceae | 8 |
| Peucephyllum schottii | A.Gray | Asteraceae | 8 |
| Phacelia affinis | A.Gray | Hydrophyllaceae | 8 |
| Phacelia arizonica | A.Gray | Hydrophyllaceae | 8 |
| Phacelia bombycina | Wooton & Standl. | Hydrophyllaceae | 8 |
| Phacelia brachyloba | (Benth.) A.Gray | Hydrophyllaceae | 8 |
| Phacelia cicutaria | Greene | Hydrophyllaceae | 8 |
| Phacelia ciliata | Benth. | Hydrophyllaceae | 8 |
| Phacelia congesta | Hook. | Hydrophyllaceae | 8 |
| Phacelia crenulata | Torr. ex S.Watson | Hydrophyllaceae | 8 |
| Phacelia cryptantha | Greene | Hydrophyllaceae | 8 |
| Phacelia distans | Benth. | Hydrophyllaceae | 8 |
| Phacelia fremontii | Torr. | Hydrophyllaceae | 8 |
| Phacelia grandiflora | (Benth.) A.Gray | Hydrophyllaceae | 8 |
| Phacelia heterophylla | Pursh | Hydrophyllaceae | 8 |
| Phacelia imbricata | Greene | Hydrophyllaceae | 8 |
| Phacelia ixodes | Kellogg | Hydrophyllaceae | 8 |
| Phacelia minor | (Harv.) Thell. | Hydrophyllaceae | 8 |
| Phacelia neglecta | M.E.Jones | Hydrophyllaceae | 8 |
| Phacelia pachyphylla | A.Gray | Hydrophyllaceae | 8 |
| Phacelia parryi | Torr. | Hydrophyllaceae | 8 |
| Phacelia patuliflora | (Engelm. & A.Gray) A.Gray | Hydrophyllaceae | 8 |
| Phacelia pedicellata | A.Gray | Hydrophyllaceae | 8 |
| Phacelia platycarpa | (Cav.) Spreng. | Hydrophyllaceae | 8 |
| Phacelia popei | Torr. & A.Gray | Hydrophyllaceae | 8 |
| Phacelia ramosissima | Douglas ex Lehm. | Hydrophyllaceae | 8 |
| Phacelia secunda | J.F.Gmel. | Hydrophyllaceae | 8 |
| Phacelia stellaris | Brand | Hydrophyllaceae | 8 |
| Phacelia tanacetifolia | Benth. | Hydrophyllaceae | 8 |
| Phacelia viscida | (Benth. ex Lindl.) Torr. | Hydrophyllaceae | 8 |
| Phalaris arundinacea | L. | Poaceae | 8 |
| Phalaris caroliniana | Walter | Poaceae | 8 |
| Phanerophlebia umbonata | Underw. | Dryopteridaceae | 8 |
| Phaseolus angustissimus | A.Gray | Fabaceae | 8 |
| Phaseolus coccineus | L. | Fabaceae | 8 |
| Phaseolus filiformis | Benth. | Fabaceae | 8 |
| Phaseolus grayanus | Wooton & Standl. | Fabaceae | 8 |
| Phaseolus lunatus | L. | Fabaceae | 8 |
| Phaseolus parvulus | Greene | Fabaceae | 8 |
| Phaseolus vulgaris | L. | Fabaceae | 8 |
| Phaulothamnus spinescens | A.Gray | Achatocarpaceae | 8 |
| Phemeranthus parviflorus | (Nutt.) Kiger | Montiaceae | 8 |
| Phenax hirtus | (Sw.) Wedd. | Urticaceae | 8 |
| Philadelphus microphyllus | A.Gray | Hydrangeaceae | 8 |
| Phlebodium pseudoaureum | (Cav.) Lellinger | Polypodiaceae | 8 |
| Phlox austromontana | Coville | Polemoniaceae | 8 |
| Phlox nana | Nutt. | Polemoniaceae | 8 |
| Pholisma arenarium | Nutt. | Lennoaceae | 8 |
| Pholisma sonorae | (Torr.) Yatsk. | Lennoaceae | 8 |
| Pholistoma auritum | (Lindl.) Lilja | Hydrophyllaceae | 8 |
| Pholistoma membranaceum | (Benth.) Constance | Hydrophyllaceae | 8 |
| Pholistoma racemosum | (Nutt. ex A.Gray) Constance | Hydrophyllaceae | 8 |
| Phoradendron bolleanum | (Seem.) Eichler | Santalaceae | 8 |
| Phoradendron brachystachyum | (DC.) Nutt. | Santalaceae | 8 |
| Phoradendron californicum | Nutt. | Santalaceae | 8 |
| Phoradendron capitellatum | Torr. ex Trel. | Santalaceae | 8 |
| Phoradendron carneum | Urb. | Santalaceae | 8 |
| Phoradendron coryae | Trel. | Santalaceae | 8 |
| Phoradendron densum | Torr. ex Trel. | Santalaceae | 8 |
| Phoradendron juniperinum | Engelm. ex A.Gray | Santalaceae | 8 |
| Phoradendron leucarpum | (Raf.) Reveal & M.C.Johnst. | Santalaceae | 8 |
| Phoradendron pauciflorum | Torr. | Santalaceae | 8 |
| Phoradendron quadrangulare | (Kunth) Griseb. | Santalaceae | 8 |
| Phragmites australis | (Cav.) Steud. | Poaceae | 8 |
| Phyla cuneifolia | (Torr.) Greene | Verbenaceae | 8 |
| Phyla lanceolata | (Michx.) Greene | Verbenaceae | 8 |
| Phyla nodiflora | (L.) Greene | Verbenaceae | 8 |
| Phyllanthus caroliniensis | Walter | Phyllanthaceae | 8 |
| Phyllanthus evanescens | Brandegee | Phyllanthaceae | 8 |
| Phyllanthus niruri | L. | Phyllanthaceae | 8 |
| Phyllanthus polygonoides | Nutt. ex Spreng. | Phyllanthaceae | 8 |
| Phyllospadix scouleri | Hook. | Zosteraceae | 8 |
| Phyllospadix torreyi | S.Watson | Zosteraceae | 8 |
| Physalis acutifolia | (Miers) Sandwith | Solanaceae | 8 |
| Physalis angulata | L. | Solanaceae | 8 |
| Physalis cordata | Mill. | Solanaceae | 8 |
| Physalis crassifolia | Benth. | Solanaceae | 8 |
| Physalis fendleri | A.Gray | Solanaceae | 8 |
| Physalis glabra | Benth. | Solanaceae | 8 |
| Physalis hederifolia | A.Gray | Solanaceae | 8 |
| Physalis longifolia | Nutt. | Solanaceae | 8 |
| Physalis neomexicana | Rydb. | Solanaceae | 8 |
| Physalis nicandroides | Schltdl. | Solanaceae | 8 |
| Physalis patula | Mill. | Solanaceae | 8 |
| Physalis philadelphica | Lam. | Solanaceae | 8 |
| Physalis pubescens | L. | Solanaceae | 8 |
| Physalis solanacea | (Schltdl.) Axelius | Solanaceae | 8 |
| Physalis virginiana | Mill. | Solanaceae | 8 |
| Physaria fendleri | (A.Gray) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria gordonii | (A.Gray) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria kingii | (S.Watson) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria purpurea | (A.Gray) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physocarpus intermedius | (Rydb.) C.K.Schneid. | Rosaceae | 8 |
| Physodium adenodes | (Goldberg) Fryxell | Malvaceae | 8 |
| Phytolacca americana | L. | Phytolaccaceae | 8 |
| Phytolacca icosandra | L. | Phytolaccaceae | 8 |
| Pickeringia montana | Nutt. | Fabaceae | 8 |
| Picradeniopsis absinthifolia | (Benth.) B.G.Baldwin | Asteraceae | 8 |
| Picradeniopsis multiflora | (Hook. & Arn.) B.G.Baldwin | Asteraceae | 8 |
| Picramnia antidesma | Sw. | Picramniaceae | 8 |
| Pilea microphylla | (L.) Liebm. | Urticaceae | 8 |
| Pilosocereus leucocephalus | (Poselg.) Byles & G.D.Rowley | Cactaceae | 8 |
| Pilosocereus purpusii | (Britton & Rose) Byles & G.D.Rowley | Cactaceae | 8 |
| Pilostyles thurberi | A.Gray | Apodanthaceae | 8 |
| Pilularia americana | A.Br. | Marsileaceae | 8 |
| Pinaropappus roseus | (Less.) Less. | Asteraceae | 8 |
| Pinguicula moranensis | Kunth | Lentibulariaceae | 8 |
| Pinguicula oblongiloba | A.DC. | Lentibulariaceae | 8 |
| Pinguicula parvifolia | B.L.Rob. | Lentibulariaceae | 8 |
| Pinus arizonica | Engelm. | Pinaceae | 8 |
| Pinus attenuata | Lemmon | Pinaceae | 8 |
| Pinus cembroides | Zucc. | Pinaceae | 8 |
| Pinus contorta | Douglas ex Loudon | Pinaceae | 8 |
| Pinus coulteri | D.Don | Pinaceae | 8 |
| Pinus devoniana | Lindl. | Pinaceae | 8 |
| Pinus durangensis | Martínez | Pinaceae | 8 |
| Pinus engelmannii | Carrière | Pinaceae | 8 |
| Pinus flexilis | E.James | Pinaceae | 8 |
| Pinus hartwegii | Lindl. | Pinaceae | 8 |
| Pinus herrerae | Mast. | Pinaceae | 8 |
| Pinus jeffreyi | A.Murray bis & al. | Pinaceae | 8 |
| Pinus lambertiana | Douglas | Pinaceae | 8 |
| Pinus leiophylla | Schiede ex Schltdl. & Cham. | Pinaceae | 8 |
| Pinus lumholtzii | B.L.Rob. & Fernald | Pinaceae | 8 |
| Pinus maximinoi | H.E.Moore | Pinaceae | 8 |
| Pinus monophylla | Torr. & Frém. | Pinaceae | 8 |
| Pinus muricata | D.Don | Pinaceae | 8 |
| Pinus oocarpa | Schiede | Pinaceae | 8 |
| Pinus ponderosa | Douglas ex C.Lawson | Pinaceae | 8 |
| Pinus praetermissa | Styles & McVaugh | Pinaceae | 8 |
| Pinus pseudostrobus | Lindl. | Pinaceae | 8 |
| Pinus quadrifolia | Parl. ex Sudw. | Pinaceae | 8 |
| Pinus radiata | D.Don | Pinaceae | 8 |
| Pinus strobiformis | Engelm. | Pinaceae | 8 |
| Pinus teocote | Schied. ex Schltdl. & Cham. | Pinaceae | 8 |
| Piper aduncum | L. | Piperaceae | 8 |
| Piper auritum | Kunth | Piperaceae | 8 |
| Piper hispidum | Sw. | Piperaceae | 8 |
| Piptochaetium fimbriatum | (Kunth) Hitchc. | Poaceae | 8 |
| Piptochaetium pringlei | (Beal) Parodi | Poaceae | 8 |
| Piqueria trinervia | Cav. | Asteraceae | 8 |
| Piranhea mexicana | (Standl.) Radcl.-Sm. | Picrodendraceae | 8 |
| Pisonia aculeata | L. | Nyctaginaceae | 8 |
| Pisonia capitata | (S.Watson) Standl. | Nyctaginaceae | 8 |
| Pistia stratiotes | L. | Araceae | 8 |
| Pitcairnia heterophylla | (Lindl.) Beer | Bromeliaceae | 8 |
| Pithecellobium dulce | (Roxb.) Benth. | Fabaceae | 8 |
| Pithecellobium lanceolatum | (Humb. & Bonpl. ex Willd.) Benth. | Fabaceae | 8 |
| Pithecellobium unguis-cati | (L.) Benth. | Fabaceae | 8 |
| Pityrocarpa obliqua | (Pers.) Brenan | Fabaceae | 8 |
| Pityrogramma calomelanos | (L.) Link | Pteridaceae | 8 |
| Pityrogramma trifoliata | (L.) R.M.Tryon | Pteridaceae | 8 |
| Plagiobothrys acanthocarpus | (Piper) I.M.Johnst. | Boraginaceae | 8 |
| Plagiobothrys arizonicus | (A.Gray) Greene ex A.Gray | Boraginaceae | 8 |
| Plagiobothrys bracteatus | (Howell) I.M.Johnst. | Boraginaceae | 8 |
| Plagiobothrys collinus | (Phil.) I.M.Johnst. | Boraginaceae | 8 |
| Plagiobothrys nothofulvus | (A.Gray) A.Gray | Boraginaceae | 8 |
| Plagiobothrys tenellus | (Nutt.) A.Gray | Boraginaceae | 8 |
| Planodes virginicum | (L.) Greene | Brassicaceae | 8 |
| Plantago australis | Lam. | Plantaginaceae | 8 |
| Plantago elongata | Pursh | Plantaginaceae | 8 |
| Plantago erecta | E.Morris | Plantaginaceae | 8 |
| Plantago heterophylla | Nutt. | Plantaginaceae | 8 |
| Plantago hookeriana | Fisch. & C.A.Mey. | Plantaginaceae | 8 |
| Plantago nivea | Kunth | Plantaginaceae | 8 |
| Plantago ovata | Forssk. | Plantaginaceae | 8 |
| Plantago patagonica | Jacq. | Plantaginaceae | 8 |
| Plantago rhodosperma | Decne. | Plantaginaceae | 8 |
| Plantago virginica | L. | Plantaginaceae | 8 |
| Platanthera brevifolia | (Greene) Senghas | Orchidaceae | 8 |
| Platanthera cooperi | (S.Watson) R.M.Bateman | Orchidaceae | 8 |
| Platanthera dilatata | (Pursh) Lindl. ex L.C.Beck | Orchidaceae | 8 |
| Platanthera elongata | (Rydb.) R.M.Bateman | Orchidaceae | 8 |
| Platanthera leptopetala | (Rydb.) R.M.Bateman | Orchidaceae | 8 |
| Platanthera sparsiflora | (S.Watson) Schltr. | Orchidaceae | 8 |
| Platanthera unalascensis | (Spreng.) Kurtz | Orchidaceae | 8 |
| Platanus racemosa | Nutt. | Platanaceae | 8 |
| Platanus wrightii | S.Watson | Platanaceae | 8 |
| Platymiscium trifoliolatum | Benth. | Fabaceae | 8 |
| Platystemon californicus | Benth. | Papaveraceae | 8 |
| Plectocephalus americanus | (Nutt.) D.Don | Asteraceae | 8 |
| Pleopeltis crassinervata | T.Moore | Polypodiaceae | 8 |
| Pleopeltis guttata | (Maxon) E.G.Andrews & Windham | Polypodiaceae | 8 |
| Pleopeltis macrocarpa | (Bory ex Willd.) Kaulf. | Polypodiaceae | 8 |
| Pleopeltis michauxiana | (Weath.) Hickey & Sprunt | Polypodiaceae | 8 |
| Pleopeltis polylepis | (A.Roem. ex Kunze) T.Moore | Polypodiaceae | 8 |
| Pleopeltis polypodioides | (L.) E.G.Andrews & Windham | Polypodiaceae | 8 |
| Pleradenophora bilocularis | (S.Watson) Esser & A.L.Melo | Euphorbiaceae | 8 |
| Pleurocoronis laphamioides | (Rose) R.M.King & H.Rob. | Asteraceae | 8 |
| Pleurocoronis pluriseta | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Pluchea carolinensis | (Jacq.) G.Don | Asteraceae | 8 |
| Pluchea odorata | (L.) Cass. | Asteraceae | 8 |
| Pluchea parvifolia | (A.Gray) R.K.Godfrey | Asteraceae | 8 |
| Pluchea salicifolia | (Mill.) S.F.Blake | Asteraceae | 8 |
| Pluchea sericea | (Nutt.) Coville | Asteraceae | 8 |
| Plumbago zeylanica | L. | Plumbaginaceae | 8 |
| Plumeria rubra | L. | Apocynaceae | 8 |
| Poa bigelovii | Vasey ex Scribn. | Poaceae | 8 |
| Poa fendleriana | (Steud.) Vasey | Poaceae | 8 |
| Poa pratensis | L. | Poaceae | 8 |
| Poa secunda | J.Presl | Poaceae | 8 |
| Pogogyne nudiuscula | A.Gray | Lamiaceae | 8 |
| Pogogyne serpylloides | (Torr.) A.Gray | Lamiaceae | 8 |
| Polemonium pauciflorum | S.Watson | Polemoniaceae | 8 |
| Poliomintha incana | (Torr.) A.Gray | Lamiaceae | 8 |
| Polycarpon tetraphyllum | (L.) L. | Caryophyllaceae | 8 |
| Polyclathra cucumerina | Bertol. | Cucurbitaceae | 8 |
| Polygala magdalenae | Brandegee | Polygalaceae | 8 |
| Polypodium californicum | Kaulf. | Polypodiaceae | 8 |
| Polypodium hesperium | Maxon | Polypodiaceae | 8 |
| Polypodium plesiosorum | Kunze | Polypodiaceae | 8 |
| Polypodium scouleri | Hook. & Grev. | Polypodiaceae | 8 |
| Polypogon interruptus | Kunth | Poaceae | 8 |
| Polypremum procumbens | L. | Tetrachondraceae | 8 |
| Polystemma cordifolium | (A.Gray) McDonnell & Fishbein | Apocynaceae | 8 |
| Polystemma pilosum | (Benth.) Morillo | Apocynaceae | 8 |
| Polystichum munitum | (Kaulf.) C.Presl | Dryopteridaceae | 8 |
| Pombalia glabra | (Dowell) Paula-Souza | Violaceae | 8 |
| Pombalia verticillata | (Ortega) Paula-Souza | Violaceae | 8 |
| Ponthieva racemosa | (Walter) C.Mohr | Orchidaceae | 8 |
| Populus angustifolia | E.James | Salicaceae | 8 |
| Populus brandegeei | C.K.Schneid. | Salicaceae | 8 |
| Populus deltoides | W.Bartram ex Marshall | Salicaceae | 8 |
| Populus fremontii | S.Watson | Salicaceae | 8 |
| Populus tremuloides | Michx. | Salicaceae | 8 |
| Porophyllum crassifolium | S.Watson | Asteraceae | 8 |
| Porophyllum gracile | Benth. | Asteraceae | 8 |
| Porophyllum linaria | (Cav.) DC. | Asteraceae | 8 |
| Porophyllum punctatum | S.F.Blake | Asteraceae | 8 |
| Porophyllum ruderale | (Jacq.) Cass. | Asteraceae | 8 |
| Porophyllum scoparium | A.Gray | Asteraceae | 8 |
| Portulaca californica | D.Legrand | Portulacaceae | 8 |
| Portulaca halimoides | L. | Portulacaceae | 8 |
| Portulaca pilosa | L. | Portulacaceae | 8 |
| Portulaca suffrutescens | Engelm. | Portulacaceae | 8 |
| Portulaca umbraticola | Kunth | Portulacaceae | 8 |
| Potamogeton diversifolius | Raf. | Potamogetonaceae | 8 |
| Potamogeton foliosus | Raf. | Potamogetonaceae | 8 |
| Potamogeton illinoensis | Morong | Potamogetonaceae | 8 |
| Potamogeton natans | L. | Potamogetonaceae | 8 |
| Potamogeton nodosus | Poir. | Potamogetonaceae | 8 |
| Potamogeton pusillus | L. | Potamogetonaceae | 8 |
| Potentilla argyrocoma | (Rydb.) Jeps. | Rosaceae | 8 |
| Potentilla biennis | Greene | Rosaceae | 8 |
| Potentilla bolanderi | (A.Gray) Greene | Rosaceae | 8 |
| Potentilla clevelandii | Greene | Rosaceae | 8 |
| Potentilla gracilis | Douglas ex Hook. | Rosaceae | 8 |
| Potentilla hippiana | Lehm. | Rosaceae | 8 |
| Potentilla lindleyi | Greene | Rosaceae | 8 |
| Potentilla rivalis | Nutt. | Rosaceae | 8 |
| Potentilla saxosa | Lemmon & S.A.Lemmon ex Greene | Rosaceae | 8 |
| Potentilla thurberi | A.Gray | Rosaceae | 8 |
| Potentilla truncata | (Rydb.) Jeps. | Rosaceae | 8 |
| Pouteria sapota | (Jacq.) H.E.Moore & Stearn | Sapotaceae | 8 |
| Pouzolzia occidentalis | (Liebm.) Wedd. | Urticaceae | 8 |
| Prenanthella exigua | (A.Gray) Rydb. | Asteraceae | 8 |
| Primula clevelandii | (Greene) A.R.Mast & Reveal | Primulaceae | 8 |
| Primula rusbyi | Greene | Primulaceae | 8 |
| Pristimera celastroides | (Kunth) A.C.Sm. | Celastraceae | 8 |
| Priva aspera | Kunth | Verbenaceae | 8 |
| Priva lappulacea | (L.) Pers. | Verbenaceae | 8 |
| Priva mexicana | (L.) Pers. | Verbenaceae | 8 |
| Proboscidea althaeifolia | (Benth.) Decne. | Martyniaceae | 8 |
| Proboscidea louisianica | (Mill.) Thell. | Martyniaceae | 8 |
| Proboscidea parviflora | (Wooton) Wooton & Standl. | Martyniaceae | 8 |
| Prunella vulgaris | L. | Lamiaceae | 8 |
| Prunus emarginata | (Douglas ex Hook.) Eaton | Rosaceae | 8 |
| Prunus fasciculata | (Torr.) A.Gray | Rosaceae | 8 |
| Prunus fremontii | S.Watson | Rosaceae | 8 |
| Prunus ilicifolia | (Nutt. ex Hook. & Arn.) D.Dietr. | Rosaceae | 8 |
| Prunus rhamnoides | Koehne | Rosaceae | 8 |
| Prunus serotina | Ehrh. | Rosaceae | 8 |
| Prunus virginiana | L. | Rosaceae | 8 |
| Psacalium decompositum | (A.Gray) H.Rob. & Brettell | Asteraceae | 8 |
| Psacalium peltatum | Cass. | Asteraceae | 8 |
| Psacalium sinuatum | (Cerv.) H.Rob. & Brettell | Asteraceae | 8 |
| Psathyrotes ramosissima | A.Gray | Asteraceae | 8 |
| Pseuderanthemum praecox | (Benth.) Leonard | Acanthaceae | 8 |
| Pseudobombax ellipticum | (Kunth) Dugand | Malvaceae | 8 |
| Pseudobombax palmeri | (S.Watson) Dugand | Malvaceae | 8 |
| Pseudognaphalium attenuatum | (DC.) Anderb. | Asteraceae | 8 |
| Pseudognaphalium biolettii | Anderb. | Asteraceae | 8 |
| Pseudognaphalium californicum | (DC.) Anderb. | Asteraceae | 8 |
| Pseudognaphalium canescens | (DC.) Anderb. | Asteraceae | 8 |
| Pseudognaphalium leucocephalum | (A.Gray) Anderb. | Asteraceae | 8 |
| Pseudognaphalium macounii | (Greene) Kartesz | Asteraceae | 8 |
| Pseudognaphalium ramosissimum | (Nutt.) Anderb. | Asteraceae | 8 |
| Pseudognaphalium stramineum | (Kunth) Anderb. | Asteraceae | 8 |
| Pseudognaphalium thermale | (E.E.Nelson) G.L.Nesom | Asteraceae | 8 |
| Pseudogynoxys chenopodioides | (Kunth) Cabrera | Asteraceae | 8 |
| Pseudoroegneria spicata | (Pursh) Á.Löve | Poaceae | 8 |
| Pseudorontium cyathiferum | (Benth.) Rothm. | Plantaginaceae | 8 |
| Pseudosmodingium perniciosum | (Kunth) Engl. | Anacardiaceae | 8 |
| Pseudotsuga menziesii | (Mirb.) Franco | Pinaceae | 8 |
| Pseudoziziphus parryi | (Torr.) Hauenschild | Rhamnaceae | 8 |
| Psidium guineense | Sw. | Myrtaceae | 8 |
| Psilactis asteroides | A.Gray | Asteraceae | 8 |
| Psilocarphus brevissimus | Nutt. | Asteraceae | 8 |
| Psilocarphus tenellus | Nutt. | Asteraceae | 8 |
| Psilostrophe cooperi | (A.Gray) Greene | Asteraceae | 8 |
| Psilostrophe gnaphalodes | DC. | Asteraceae | 8 |
| Psilostrophe tagetina | (Nutt.) Greene | Asteraceae | 8 |
| Psilotum complanatum | Sw. | Psilotaceae | 8 |
| Psilotum nudum | (L.) P.Beauv. | Psilotaceae | 8 |
| Psittacanthus calyculatus | G.Don | Loranthaceae | 8 |
| Psittacanthus rhynchanthus | (Benth.) Kuijt | Loranthaceae | 8 |
| Psittacanthus sonorae | (S.Watson) Kuijt | Loranthaceae | 8 |
| Psorodendron schottii | (Torr.) Rydb. | Fabaceae | 8 |
| Psorodendron spinosum | (A.Gray) Rydb. | Fabaceae | 8 |
| Psorothamnus emoryi | (A.Gray) Rydb. | Fabaceae | 8 |
| Psychotria erythrocarpa | Schltdl. | Rubiaceae | 8 |
| Ptelea aptera | Parry | Rutaceae | 8 |
| Ptelea trifoliata | L. | Rutaceae | 8 |
| Pteridium aquilinum | (L.) Kuhn | Dennstaedtiaceae | 8 |
| Pteridium caudatum | (L.) Maxon | Dennstaedtiaceae | 8 |
| Pteridium esculentum | (G.Forst.) Cockayne | Dennstaedtiaceae | 8 |
| Pteris longifolia | L. | Pteridaceae | 8 |
| Pterospora andromedea | Nutt. | Ericaceae | 8 |
| Pterostegia drymarioides | Fisch. & C.A.Mey. | Polygonaceae | 8 |
| Purshia glandulosa | Curran | Rosaceae | 8 |
| Purshia mexicana | (D.Don) S.L.Welsh | Rosaceae | 8 |
| Purshia stansburyana | (Torr.) Henrickson | Rosaceae | 8 |
| Pyrola aphylla | Sm. | Ericaceae | 8 |
| Pyrostegia venusta | (Ker Gawl.) Miers | Bignoniaceae | 8 |
| Pyrrhopappus pauciflorus | (D.Don) DC. | Asteraceae | 8 |
| Quercus agrifolia | Née | Fagaceae | 8 |
| Quercus albocincta | Trel. | Fagaceae | 8 |
| Quercus arizonica | Sarg. | Fagaceae | 8 |
| Quercus berberidifolia | Liebm. | Fagaceae | 8 |
| Quercus brandegeei | Goldman | Fagaceae | 8 |
| Quercus calophylla | Schltdl. & Cham. | Fagaceae | 8 |
| Quercus castanea | Née | Fagaceae | 8 |
| Quercus cedrosensis | C.H.Mull. | Fagaceae | 8 |
| Quercus chihuahuensis | Trel. | Fagaceae | 8 |
| Quercus chrysolepis | Liebm. | Fagaceae | 8 |
| Quercus cornelius-mulleri | Nixon & K.P.Steele | Fagaceae | 8 |
| Quercus deserticola | Trel. | Fagaceae | 8 |
| Quercus dumosa | Nutt. | Fagaceae | 8 |
| Quercus elliptica | Née | Fagaceae | 8 |
| Quercus emoryi | Torr. | Fagaceae | 8 |
| Quercus engelmannii | Greene | Fagaceae | 8 |
| Quercus gambelii | Nutt. | Fagaceae | 8 |
| Quercus grisea | Liebm. | Fagaceae | 8 |
| Quercus hypoleucoides | A.Camus | Fagaceae | 8 |
| Quercus jonesii | Trel. | Fagaceae | 8 |
| Quercus kelloggii | Newb. | Fagaceae | 8 |
| Quercus laeta | Liebm. | Fagaceae | 8 |
| Quercus magnoliifolia | Née | Fagaceae | 8 |
| Quercus oblongifolia | Torr. | Fagaceae | 8 |
| Quercus palmeri | (Engelm.) Engelm. | Fagaceae | 8 |
| Quercus peninsularis | Trel. | Fagaceae | 8 |
| Quercus rugosa | Née | Fagaceae | 8 |
| Quercus sideroxyla | Bonpl. | Fagaceae | 8 |
| Quercus tomentella | Engelm. | Fagaceae | 8 |
| Quercus toumeyi | Sarg. | Fagaceae | 8 |
| Quercus turbinella | Greene | Fagaceae | 8 |
| Quercus wislizeni | A.DC. | Fagaceae | 8 |
| Quincula lobata | (Torr.) Raf. | Solanaceae | 8 |
| Rafinesquia californica | Nutt. | Asteraceae | 8 |
| Rafinesquia neomexicana | A.Gray | Asteraceae | 8 |
| Randia aculeata | L. | Rubiaceae | 8 |
| Randia capitata | DC. | Rubiaceae | 8 |
| Randia echinocarpa | Moc. & Sessé ex DC. | Rubiaceae | 8 |
| Randia obcordata | S.Watson | Rubiaceae | 8 |
| Randia thurberi | S.Watson | Rubiaceae | 8 |
| Ranunculus alismifolius | Geyer ex Benth. | Ranunculaceae | 8 |
| Ranunculus californicus | Benth. | Ranunculaceae | 8 |
| Ranunculus harveyi | (A.Gray) Britton | Ranunculaceae | 8 |
| Ranunculus hebecarpus | Hook. & Arn. | Ranunculaceae | 8 |
| Ranunculus macranthus | Scheele | Ranunculaceae | 8 |
| Ranunculus minimus | E.H.L.Krause | Ranunculaceae | 8 |
| Ranunculus petiolaris | Kunth | Ranunculaceae | 8 |
| Ranunculus trichophyllus | Chaix | Ranunculaceae | 8 |
| Ranunculus uncinatus | D.Don ex G.Don | Ranunculaceae | 8 |
| Ratibida columnifera | (Nutt.) Wooton & Standl. | Asteraceae | 8 |
| Ratibida tagetes | (E.James) Barnhart | Asteraceae | 8 |
| Rauvolfia tetraphylla | L. | Apocynaceae | 8 |
| Rhamnus crocea | Nutt. | Rhamnaceae | 8 |
| Rhinotropis cornuta | (Kellogg) J.R.Abbott | Polygalaceae | 8 |
| Rhinotropis lindheimeri | (A.Gray) J.R.Abbott | Polygalaceae | 8 |
| Rhipsalis baccifera | (Sol. ex J.S.Muell.) Stearn | Cactaceae | 8 |
| Rhizophora mangle | L. | Rhizophoraceae | 8 |
| Rhus aromatica | Aiton | Anacardiaceae | 8 |
| Rhus glabra | L. | Anacardiaceae | 8 |
| Rhus integrifolia | (Nutt.) Benth. & Hook.f. ex W.H.Brewer & S.Watson | Anacardiaceae | 8 |
| Rhus microphylla | Engelm. | Anacardiaceae | 8 |
| Rhus ovata | S.Watson | Anacardiaceae | 8 |
| Rhus schiedeana | Schltdl. | Anacardiaceae | 8 |
| Rhus terebinthifolia | Schltdl. & Cham. | Anacardiaceae | 8 |
| Rhus virens | Lindh. ex A.Gray | Anacardiaceae | 8 |
| Rhynchosia americana | (Mill.) Metz | Fabaceae | 8 |
| Rhynchosia edulis | Griseb. | Fabaceae | 8 |
| Rhynchosia latifolia | Nutt. | Fabaceae | 8 |
| Rhynchosia minima | (L.) DC. | Fabaceae | 8 |
| Rhynchosia precatoria | (Humb. & Bonpl. ex Willd.) DC. | Fabaceae | 8 |
| Rhynchosia senna | Gillies ex Hook. & Arn. | Fabaceae | 8 |
| Rhynchosida physocalyx | (A.Gray) Fryxell | Malvaceae | 8 |
| Rhynchospora nervosa | (Vahl) Boeckeler | Cyperaceae | 8 |
| Ribes canthariforme | Wiggins | Grossulariaceae | 8 |
| Ribes cereum | Douglas | Grossulariaceae | 8 |
| Ribes ciliatum | Humb. & Bonpl. ex Schult. | Grossulariaceae | 8 |
| Ribes indecorum | Eastw. | Grossulariaceae | 8 |
| Ribes malvaceum | Sm. | Grossulariaceae | 8 |
| Ribes mescalerium | Coville | Grossulariaceae | 8 |
| Ribes quercetorum | Greene | Grossulariaceae | 8 |
| Ribes speciosum | Pursh | Grossulariaceae | 8 |
| Ribes tortuosum | Benth. | Grossulariaceae | 8 |
| Ribes viburnifolium | A.Gray | Grossulariaceae | 8 |
| Richardia scabra | L. | Rubiaceae | 8 |
| Rivina humilis | L. | Petiveriaceae | 8 |
| Robinia neomexicana | A.Gray | Fabaceae | 8 |
| Rogiera amoena | Planch. | Rubiaceae | 8 |
| Roldana angulifolia | (DC.) H.Rob. & Brettell | Asteraceae | 8 |
| Roldana barba-johannis | (DC.) H.Rob. & Brettell | Asteraceae | 8 |
| Roldana hartwegii | (Benth.) H.Rob. & Brettell | Asteraceae | 8 |
| Romneya coulteri | Harv. | Papaveraceae | 8 |
| Romneya trichocalyx | Eastw. | Papaveraceae | 8 |
| Rorippa curvisiliqua | (Hook.) Bessey ex Britton | Brassicaceae | 8 |
| Rorippa palustris | (L.) Besser | Brassicaceae | 8 |
| Rorippa teres | (Michx.) Stuckey | Brassicaceae | 8 |
| Rosa californica | Cham. & Schltdl. | Rosaceae | 8 |
| Rosa minutifolia | Engelm. | Rosaceae | 8 |
| Rosa woodsii | Lindl. | Rosaceae | 8 |
| Rotala ramosior | (L.) Koehne | Lythraceae | 8 |
| Rubus coriifolius | Liebm. | Rosaceae | 8 |
| Rubus deliciosus | Torr. | Rosaceae | 8 |
| Rubus flagellaris | Willd. | Rosaceae | 8 |
| Rubus idaeus | L. | Rosaceae | 8 |
| Rubus parviflorus | Nutt. | Rosaceae | 8 |
| Rubus ursinus | Cham. & Schltdl. | Rosaceae | 8 |
| Ruellia blechum | L. | Acanthaceae | 8 |
| Ruellia californica | (Vasey & Rose) I.M.Johnst. | Acanthaceae | 8 |
| Ruellia ciliatiflora | Hook. | Acanthaceae | 8 |
| Ruellia inundata | Kunth | Acanthaceae | 8 |
| Ruellia lactea | Cav. | Acanthaceae | 8 |
| Ruellia leucantha | Brandegee | Acanthaceae | 8 |
| Ruellia parryi | A.Gray | Acanthaceae | 8 |
| Ruellia simplex | C.Wright | Acanthaceae | 8 |
| Ruellia tuberosa | L. | Acanthaceae | 8 |
| Rumex altissimus | Alph.Wood | Polygonaceae | 8 |
| Rumex californicus | Rech.f. | Polygonaceae | 8 |
| Rumex hymenosepalus | Torr. | Polygonaceae | 8 |
| Rumex maritimus | L. | Polygonaceae | 8 |
| Rumex salicifolius | Weinm. | Polygonaceae | 8 |
| Rumfordia floribunda | DC. | Asteraceae | 8 |
| Ruppia cirrhosa | (Petagna) Grande | Ruppiaceae | 8 |
| Ruppia maritima | L. | Ruppiaceae | 8 |
| Russelia equisetiformis | Schltdl. & Cham. | Plantaginaceae | 8 |
| Russelia sarmentosa | Jacq. | Plantaginaceae | 8 |
| Sabulina douglasii | (Fenzl ex Torr. & A.Gray) Dillenb. & Kadereit | Caryophyllaceae | 8 |
| Sagina decumbens | (Elliott) Torr. & A.Gray | Caryophyllaceae | 8 |
| Sagina saginoides | (L.) H.Karst. | Caryophyllaceae | 8 |
| Sagittaria longiloba | Engelm. ex J.G.Sm. | Alismataceae | 8 |
| Sagittaria montevidensis | Cham. & Schltdl. | Alismataceae | 8 |
| Sairocarpus coulterianus | (Benth.) D.A.Sutton | Plantaginaceae | 8 |
| Sairocarpus nuttallianus | (Benth.) D.A.Sutton | Plantaginaceae | 8 |
| Salicornia bigelovii | Torr. | Chenopodiaceae | 8 |
| Salicornia pacifica | Standl. | Chenopodiaceae | 8 |
| Salix bonplandiana | Kunth | Salicaceae | 8 |
| Salix exigua | Nutt. | Salicaceae | 8 |
| Salix gooddingii | C.R.Ball | Salicaceae | 8 |
| Salix humboldtiana | Willd. | Salicaceae | 8 |
| Salix laevigata | Bebb | Salicaceae | 8 |
| Salix lasiolepis | Benth. | Salicaceae | 8 |
| Salix nigra | Marshall | Salicaceae | 8 |
| Salix scouleriana | Barratt | Salicaceae | 8 |
| Salix taxifolia | Kunth | Salicaceae | 8 |
| Salpianthus purpurascens | (Cav. ex Lag.) Hook. & Arn. | Nyctaginaceae | 8 |
| Saltugilia australis | (H.Mason & A.D.Grant) L.A.Johnson | Polemoniaceae | 8 |
| Salvia apiana | Jeps. | Lamiaceae | 8 |
| Salvia beltraniorum | J.G.González, Pío-León & Art.Castro | Lamiaceae | 8 |
| Salvia brandegeei | Munz | Lamiaceae | 8 |
| Salvia carduacea | Benth. | Lamiaceae | 8 |
| Salvia clevelandii | (A.Gray) Greene | Lamiaceae | 8 |
| Salvia columbariae | Benth. | Lamiaceae | 8 |
| Salvia crucis | Epling | Lamiaceae | 8 |
| Salvia elegans | Vahl | Lamiaceae | 8 |
| Salvia eremostachya | Jeps. | Lamiaceae | 8 |
| Salvia hispanica | L. | Lamiaceae | 8 |
| Salvia iodantha | Fernald | Lamiaceae | 8 |
| Salvia lasiantha | Benth. | Lamiaceae | 8 |
| Salvia lasiocephala | Hook. & Arn. | Lamiaceae | 8 |
| Salvia lavanduloides | Kunth | Lamiaceae | 8 |
| Salvia leucophylla | Greene | Lamiaceae | 8 |
| Salvia mellifera | Greene | Lamiaceae | 8 |
| Salvia mexicana | L. | Lamiaceae | 8 |
| Salvia microphylla | Kunth | Lamiaceae | 8 |
| Salvia misella | Kunth | Lamiaceae | 8 |
| Salvia mohavensis | Greene | Lamiaceae | 8 |
| Salvia munzii | Epling | Lamiaceae | 8 |
| Salvia occidentalis | Sw. | Lamiaceae | 8 |
| Salvia pachyphylla | Epling ex Munz | Lamiaceae | 8 |
| Salvia polystachia | Cav. | Lamiaceae | 8 |
| Salvia prunelloides | Kunth | Lamiaceae | 8 |
| Salvia purpurea | Cav. | Lamiaceae | 8 |
| Salvia reflexa | Hornem. | Lamiaceae | 8 |
| Salvia regla | Cav. | Lamiaceae | 8 |
| Salvia tiliifolia | Vahl | Lamiaceae | 8 |
| Salvia vaseyi | (Porter) Parish | Lamiaceae | 8 |
| Sambucus canadensis | L. | Viburnaceae | 8 |
| Sambucus cerulea | Raf. | Viburnaceae | 8 |
| Samolus ebracteatus | Kunth | Primulaceae | 8 |
| Samolus parviflorus | Raf. | Primulaceae | 8 |
| Sanicula arguta | Greene ex J.M.Coult. & Rose | Apiaceae | 8 |
| Sanicula bipinnatifida | Douglas | Apiaceae | 8 |
| Sanicula crassicaulis | Poepp. ex DC. | Apiaceae | 8 |
| Sanicula liberta | Cham. & Schltdl. | Apiaceae | 8 |
| Sanicula tuberosa | Torr. | Apiaceae | 8 |
| Sapindus drummondii | Hook. & Arn. | Sapindaceae | 8 |
| Sapindus saponaria | L. | Sapindaceae | 8 |
| Sapium lateriflorum | Hemsl. | Euphorbiaceae | 8 |
| Sarcobatus vermiculatus | (Hook.) Torr. | Sarcobataceae | 8 |
| Sarcodes sanguinea | Torr. | Ericaceae | 8 |
| Sarcoglottis sceptrodes | (Rchb.f.) Schltr. | Orchidaceae | 8 |
| Sarcoglottis schaffneri | (Rchb.f.) Ames | Orchidaceae | 8 |
| Sarcomphalus amole | (Sessé & Moc.) Hauenschild | Rhamnaceae | 8 |
| Scaevola plumieri | (L.) Vahl | Goodeniaceae | 8 |
| Schaefferia cuneifolia | A.Gray | Celastraceae | 8 |
| Schiedeella affinis | (C.Schweinf.) Salazar | Orchidaceae | 8 |
| Schisandra glabra | (Brickell) Rehder | Schisandraceae | 8 |
| Schistophragma intermedium | (A.Gray) Pennell | Plantaginaceae | 8 |
| Schizachyrium sanguineum | (Retz.) Alston | Poaceae | 8 |
| Schizocarpum palmeri | Cogn. & Rose | Cucurbitaceae | 8 |
| Schkuhria pinnata | (Lam.) Kuntze ex Thell. | Asteraceae | 8 |
| Schoenoplectus acutus | (Muhl. ex Bigelow) Á.Löve & D.Löve | Cyperaceae | 8 |
| Schoenoplectus americanus | (Pers.) Volkart | Cyperaceae | 8 |
| Schoenoplectus californicus | (C.A.Mey.) Soják | Cyperaceae | 8 |
| Schoenoplectus pungens | (Vahl) Palla | Cyperaceae | 8 |
| Scirpus microcarpus | J.Presl & C.Presl | Cyperaceae | 8 |
| Scleria muehlenbergii | Steud. | Cyperaceae | 8 |
| Sclerocactus intertextus | (Engelm.) N.P.Taylor | Cactaceae | 8 |
| Sclerocarpus divaricatus | (Benth.) Benth. & Hook.f. ex Hemsl. | Asteraceae | 8 |
| Sclerocarpus uniserialis | (Hook.) Benth. & Hook.f. ex Hemsl. | Asteraceae | 8 |
| Scleropogon brevifolius | Phil. | Poaceae | 8 |
| Scoparia dulcis | L. | Plantaginaceae | 8 |
| Scrophularia californica | Cham. & Schltdl. | Scrophulariaceae | 8 |
| Scutellaria mexicana | (Torr.) A.J.Paton | Lamiaceae | 8 |
| Scutellaria potosina | Brandegee | Lamiaceae | 8 |
| Scutellaria tuberosa | Benth. | Lamiaceae | 8 |
| Sedum goldmanii | (Rose) Moran | Crassulaceae | 8 |
| Sedum jaliscanum | S.Watson | Crassulaceae | 8 |
| Sedum stelliforme | S.Watson | Crassulaceae | 8 |
| Sedum vinicolor | S.Watson | Crassulaceae | 8 |
| Selaginella arizonica | Maxon | Selaginellaceae | 8 |
| Selaginella bigelovii | Underw. | Selaginellaceae | 8 |
| Selaginella cinerascens | A.A.Eaton | Selaginellaceae | 8 |
| Selaginella eremophila | Maxon | Selaginellaceae | 8 |
| Selaginella lepidophylla | (Hook. & Grev.) Spring | Selaginellaceae | 8 |
| Selaginella pallescens | (C.Presl) Spring | Selaginellaceae | 8 |
| Selaginella peruviana | Hieron. | Selaginellaceae | 8 |
| Selaginella pilifera | A.Br. | Selaginellaceae | 8 |
| Selaginella rupincola | Underw. | Selaginellaceae | 8 |
| Selaginella sellowii | Hieron. | Selaginellaceae | 8 |
| Selaginella underwoodii | Hieron. | Selaginellaceae | 8 |
| Selaginella wrightii | Hieron. | Selaginellaceae | 8 |
| Selenicereus ocamponis | (Salm-Dyck) D.R.Hunt | Cactaceae | 8 |
| Selenicereus vagans | (K.Brandegee) Britton & Rose | Cactaceae | 8 |
| Semialarium mexicanum | (Miers) Mennega | Celastraceae | 8 |
| Senecio aphanactis | Greene | Asteraceae | 8 |
| Senecio californicus | DC. | Asteraceae | 8 |
| Senecio flaccidus | Less. | Asteraceae | 8 |
| Senecio lemmonii | A.Gray | Asteraceae | 8 |
| Senecio mohavensis | A.Gray | Asteraceae | 8 |
| Senecio sessilifolius | Hemsl. | Asteraceae | 8 |
| Senecio spartioides | Torr. & A.Gray | Asteraceae | 8 |
| Senecio wootonii | Greene | Asteraceae | 8 |
| Senegalia berlandieri | (Benth.) Britton & Rose | Fabaceae | 8 |
| Senegalia greggii | (A.Gray) Britton & Rose | Fabaceae | 8 |
| Senegalia peninsularis | Britton & Rose | Fabaceae | 8 |
| Senegalia roemeriana | (Scheele) Britton & Rose | Fabaceae | 8 |
| Senegalia wrightii | (Benth.) Britton & Rose | Fabaceae | 8 |
| Senna armata | (S.Watson) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna atomaria | (L.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna bauhinioides | (A.Gray) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna confinis | (Greene) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna covesii | (A.Gray) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna hirsuta | (L.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna lindheimeriana | (Scheele) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna multiglandulosa | (Jacq.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna obtusifolia | (L.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna occidentalis | (L.) Link | Fabaceae | 8 |
| Senna pallida | (Vahl) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna pendula | (Humb. & Bonpl. ex Willd.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna roemeriana | (Scheele) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna septemtrionalis | (Viv.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna uniflora | (Mill.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna villosa | (Mill.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna wislizeni | (A.Gray) H.S.Irwin & Barneby | Fabaceae | 8 |
| Serjania mexicana | Willd. | Sapindaceae | 8 |
| Serjania racemosa | Schum. | Sapindaceae | 8 |
| Serjania triquetra | Radlk. | Sapindaceae | 8 |
| Sesuvium portulacastrum | (L.) L. | Aizoaceae | 8 |
| Setaria grisebachii | E.Fourn. | Poaceae | 8 |
| Setaria leucopila | (Scribn. & Merr.) K.Schum. | Poaceae | 8 |
| Setaria liebmannii | E.Fourn. | Poaceae | 8 |
| Setaria parviflora | (Poir.) Kerguélen | Poaceae | 8 |
| Sibara angelorum | (S.Watson) Greene | Brassicaceae | 8 |
| Sicyos edulis | Jacq. | Cucurbitaceae | 8 |
| Sicyos laciniatus | L. | Cucurbitaceae | 8 |
| Sicyos microphyllus | Kunth | Cucurbitaceae | 8 |
| Sida acuta | Burm.f. | Malvaceae | 8 |
| Sida ciliaris | L. | Malvaceae | 8 |
| Sida cordifolia | L. | Malvaceae | 8 |
| Sida elliottii | Torr. & A.Gray | Malvaceae | 8 |
| Sida linifolia | Cav. | Malvaceae | 8 |
| Sida spinosa | L. | Malvaceae | 8 |
| Sida ulmifolia | Mill. | Malvaceae | 8 |
| Sida xanti | A.Gray | Malvaceae | 8 |
| Sidalcea malviflora | (DC.) A.Gray | Malvaceae | 8 |
| Sidalcea neomexicana | A.Gray | Malvaceae | 8 |
| Sidalcea sparsifolia | (C.L.Hitchc.) S.R.Hill | Malvaceae | 8 |
| Sideroxylon capiri | (A.DC.) Pittier | Sapotaceae | 8 |
| Sideroxylon celastrinum | (Kunth) T.D.Penn. | Sapotaceae | 8 |
| Sideroxylon lanuginosum | Michx. | Sapotaceae | 8 |
| Sideroxylon persimile | (Hemsl.) T.D.Penn. | Sapotaceae | 8 |
| Sidneya tenuifolia | (A.Gray) E.E.Schill. & Panero | Asteraceae | 8 |
| Sidotheca trilobata | (A.Gray) Reveal | Polygonaceae | 8 |
| Silene antirrhina | L. | Caryophyllaceae | 8 |
| Silene bernardina | S.Watson | Caryophyllaceae | 8 |
| Silene laciniata | Cav. | Caryophyllaceae | 8 |
| Silene scouleri | Hook. | Caryophyllaceae | 8 |
| Silene verecunda | S.Watson | Caryophyllaceae | 8 |
| Simmondsia chinensis | (Link) C.K.Schneid. | Simmondsiaceae | 8 |
| Simpsonanthus jonesii | (A.Gray) Guilliams, Hasenstab & B.G.Baldwin | Boraginaceae | 8 |
| Simsia amplexicaulis | (Cav.) Pers. | Asteraceae | 8 |
| Sisyrinchium bellum | S.Watson | Iridaceae | 8 |
| Sisyrinchium demissum | Greene | Iridaceae | 8 |
| Sisyrinchium idahoense | E.P.Bicknell | Iridaceae | 8 |
| Smallanthus maculatus | (Cav.) H.Rob. | Asteraceae | 8 |
| Smallanthus uvedalia | (L.) Mack. | Asteraceae | 8 |
| Smilax moranensis | M.Martens & Galeotti | Smilacaceae | 8 |
| Smilax spinosa | Mill. | Smilacaceae | 8 |
| Solandra maxima | (Sessé & Moc.) P.S.Green | Solanaceae | 8 |
| Solanum americanum | Mill. | Solanaceae | 8 |
| Solanum appendiculatum | Dunal | Solanaceae | 8 |
| Solanum candidum | Lindl. | Solanaceae | 8 |
| Solanum carolinense | L. | Solanaceae | 8 |
| Solanum citrullifolium | A.Braun | Solanaceae | 8 |
| Solanum deflexum | Greenm. | Solanaceae | 8 |
| Solanum demissum | Lindl. | Solanaceae | 8 |
| Solanum donianum | Walp. | Solanaceae | 8 |
| Solanum douglasii | Dunal | Solanaceae | 8 |
| Solanum elaeagnifolium | Cav. | Solanaceae | 8 |
| Solanum erianthum | D.Don | Solanaceae | 8 |
| Solanum ferrugineum | Jacq. | Solanaceae | 8 |
| Solanum grayi | Rose | Solanaceae | 8 |
| Solanum hazenii | Britton | Solanaceae | 8 |
| Solanum heterodoxum | Dunal | Solanaceae | 8 |
| Solanum hindsianum | Benth. | Solanaceae | 8 |
| Solanum hirtum | Vahl | Solanaceae | 8 |
| Solanum houstonii | Martyn | Solanaceae | 8 |
| Solanum jamesii | Torr. | Solanaceae | 8 |
| Solanum nigrescens | M.Martens & Galeotti | Solanaceae | 8 |
| Solanum rostratum | Dunal | Solanaceae | 8 |
| Solanum seaforthianum | Andrews | Solanaceae | 8 |
| Solanum stoloniferum | Schltdl. | Solanaceae | 8 |
| Solanum subinerme | Jacq. | Solanaceae | 8 |
| Solanum torvum | Sw. | Solanaceae | 8 |
| Solanum umbellatum | Mill. | Solanaceae | 8 |
| Solanum umbelliferum | Eschsch. | Solanaceae | 8 |
| Solidago altissima | L. | Asteraceae | 8 |
| Solidago confinis | A.Gray | Asteraceae | 8 |
| Solidago missouriensis | Nutt. | Asteraceae | 8 |
| Solidago velutina | DC. | Asteraceae | 8 |
| Solidago wrightii | A.Gray | Asteraceae | 8 |
| Sophora nuttalliana | B.L.Turner | Fabaceae | 8 |
| Sophora tomentosa | L. | Fabaceae | 8 |
| Spananthe paniculata | Jacq. | Apiaceae | 8 |
| Sparganium americanum | Nutt. | Typhaceae | 8 |
| Sparganium eurycarpum | Engelm. | Typhaceae | 8 |
| Spergularia macrotheca | (Hornem. ex Cham. & Schltdl.) Heynh. | Caryophyllaceae | 8 |
| Spergularia marina | (L.) Besser | Caryophyllaceae | 8 |
| Spermacoce confusa | Rendle | Rubiaceae | 8 |
| Spermacoce densiflora | (DC.) Alain | Rubiaceae | 8 |
| Spermacoce remota | Lam. | Rubiaceae | 8 |
| Spermolepis lateriflora | G.L.Nesom | Apiaceae | 8 |
| Sphaeralcea ambigua | A.Gray | Malvaceae | 8 |
| Sphaeralcea coulteri | (S.Watson) A.Gray | Malvaceae | 8 |
| Sphaeralcea digitata | (Greene) Rydb. | Malvaceae | 8 |
| Sphaeralcea emoryi | Torr. ex A.Gray | Malvaceae | 8 |
| Sphaeralcea fendleri | A.Gray | Malvaceae | 8 |
| Sphaeralcea fulva | Greene | Malvaceae | 8 |
| Sphaeralcea hastulata | A.Gray | Malvaceae | 8 |
| Sphaeralcea incana | Torr. ex A.Gray | Malvaceae | 8 |
| Sphaeralcea laxa | Wooton & Standl. | Malvaceae | 8 |
| Sphaeralcea leptophylla | (A.Gray) Rydb. | Malvaceae | 8 |
| Sphaeralcea polychroma | La Duke | Malvaceae | 8 |
| Sphagneticola trilobata | (L.) Pruski | Asteraceae | 8 |
| Sphenopholis interrupta | (Buckley) Scribn. | Poaceae | 8 |
| Sphenopholis obtusata | (Michx.) Scribn. | Poaceae | 8 |
| Spigelia hedyotidea | A.DC. | Loganiaceae | 8 |
| Spigelia scabrella | Benth. | Loganiaceae | 8 |
| Spilanthes urens | Jacq. | Asteraceae | 8 |
| Spirodela polyrhiza | (L.) Schleid. | Araceae | 8 |
| Spondias mombin | L. | Anacardiaceae | 8 |
| Spondias purpurea | L. | Anacardiaceae | 8 |
| Sporobolus contractus | Hitchc. | Poaceae | 8 |
| Sporobolus cryptandrus | (Torr.) A.Gray | Poaceae | 8 |
| Sporobolus flexuosus | (Vasey) Rydb. | Poaceae | 8 |
| Sporobolus foliosus | (Trin.) P.M.Peterson & Saarela | Poaceae | 8 |
| Sporobolus indicus | (L.) R.Br. | Poaceae | 8 |
| Sporobolus pyramidatus | (Lam.) Hitchc. | Poaceae | 8 |
| Sporobolus wrightii | Scribn. | Poaceae | 8 |
| Stachys agraria | Schltdl. & Cham. | Lamiaceae | 8 |
| Stachys ajugoides | Benth. | Lamiaceae | 8 |
| Stachys bigelovii | A.Gray | Lamiaceae | 8 |
| Stachys coccinea | Ortega | Lamiaceae | 8 |
| Stachys rigida | Nutt. ex Benth. | Lamiaceae | 8 |
| Stachys stebbinsii | G.A.Mulligan & D.B.Munro | Lamiaceae | 8 |
| Stachytarpheta frantzii | Pol. | Verbenaceae | 8 |
| Stachytarpheta indica | (L.) Vahl | Verbenaceae | 8 |
| Stachytarpheta mutabilis | (Jacq.) Vahl | Verbenaceae | 8 |
| Stanleya pinnata | (Pursh) Britton | Brassicaceae | 8 |
| Stebbinsoseris heterocarpa | (Nutt.) K.L.Chambers | Asteraceae | 8 |
| Stegnosperma halimifolium | Benth. | Stegnospermataceae | 8 |
| Stelis emarginata | (Lindl.) Soto Arenas & Solano | Orchidaceae | 8 |
| Stellaria cuspidata | D.F.K.Schltdl. | Caryophyllaceae | 8 |
| Stellaria nitens | Nutt. | Caryophyllaceae | 8 |
| Stemodia durantifolia | (L.) Sw. | Plantaginaceae | 8 |
| Stemodia pusilla | Benth. | Plantaginaceae | 8 |
| Stenandrium dulce | (Cav.) Nees | Acanthaceae | 8 |
| Stenocereus alamosensis | (J.M.Coult.) A.C.Gibson & K.E.Horak | Cactaceae | 8 |
| Stenocereus eruca | (K.Brandegee) A.C.Gibson & K.E.Horak | Cactaceae | 8 |
| Stenocereus gummosus | (Engelm.) A.C.Gibson & K.E.Horak | Cactaceae | 8 |
| Stenocereus kerberi | (K.Schum.) A.C.Gibson & K.E.Horak | Cactaceae | 8 |
| Stenocereus martinezii | (J.G.Ortega) Buxb. | Cactaceae | 8 |
| Stenocereus standleyi | (J.G.Ortega) Buxb. | Cactaceae | 8 |
| Stenocereus thurberi | (Engelm.) Buxb. | Cactaceae | 8 |
| Stenotis arenaria | (Rose) Terrell | Rubiaceae | 8 |
| Stenotis asperuloides | (Benth.) Terrell | Rubiaceae | 8 |
| Stenotis brevipes | (Rose) Terrell | Rubiaceae | 8 |
| Stenotis mucronata | (Benth.) Terrell | Rubiaceae | 8 |
| Stephanomeria diegensis | Gottlieb | Asteraceae | 8 |
| Stephanomeria exigua | Nutt. | Asteraceae | 8 |
| Stephanomeria pauciflora | (Torr.) A.Nelson | Asteraceae | 8 |
| Stephanomeria thurberi | A.Gray | Asteraceae | 8 |
| Stephanomeria virgata | Benth. | Asteraceae | 8 |
| Stevia elatior | Kunth | Asteraceae | 8 |
| Stevia lucida | Lag. | Asteraceae | 8 |
| Stevia ovata | Willd. | Asteraceae | 8 |
| Stevia plummerae | A.Gray | Asteraceae | 8 |
| Stevia salicifolia | Cav. | Asteraceae | 8 |
| Stevia serrata | Cav. | Asteraceae | 8 |
| Stevia subpubescens | Lag. | Asteraceae | 8 |
| Stevia triflora | DC. | Asteraceae | 8 |
| Stevia viscida | Kunth | Asteraceae | 8 |
| Stillingia linearifolia | S.Watson | Euphorbiaceae | 8 |
| Stillingia spinulosa | Torr. | Euphorbiaceae | 8 |
| Streptanthus bernardinus | (Greene) Parish | Brassicaceae | 8 |
| Streptanthus campestris | S.Watson | Brassicaceae | 8 |
| Streptanthus carinatus | Wright ex A.Gray | Brassicaceae | 8 |
| Streptanthus cooperi | (S.Watson) Al-Shehbaz | Brassicaceae | 8 |
| Streptanthus hallii | Jeps. | Brassicaceae | 8 |
| Streptanthus heterophyllus | Nutt. | Brassicaceae | 8 |
| Streptanthus lasiophyllus | Hook. & Arn. ex Hoover | Brassicaceae | 8 |
| Streptanthus longirostris | (S.Watson) S.Watson | Brassicaceae | 8 |
| Streptanthus simulans | (Payson) Jeps. | Brassicaceae | 8 |
| Strombocarpa pubescens | (Benth.) A.Gray | Fabaceae | 8 |
| Strychnos panamensis | Seem. | Loganiaceae | 8 |
| Stuckenia pectinata | (L.) Börner | Potamogetonaceae | 8 |
| Stylocline gnaphalioides | Nutt. | Asteraceae | 8 |
| Stylocline micropoides | A.Gray | Asteraceae | 8 |
| Stylocline sonorensis | Wiggins | Asteraceae | 8 |
| Stylomecon crassifolia | (Benth.) Elvebakk & Bjerke | Papaveraceae | 8 |
| Stylomecon heterophylla | (Benth.) G.Taylor | Papaveraceae | 8 |
| Stylosanthes guianensis | (Aubl.) Sw. | Fabaceae | 8 |
| Stylosanthes viscosa | (L.) Sw. | Fabaceae | 8 |
| Styrax argenteus | C.Presl | Styracaceae | 8 |
| Suaeda californica | S.Watson | Chenopodiaceae | 8 |
| Suaeda nigra | (Raf.) J.F.Macbr. | Chenopodiaceae | 8 |
| Suaeda taxifolia | (Standl.) Standl. | Chenopodiaceae | 8 |
| Swietenia humilis | Zucc. | Meliaceae | 8 |
| Swietenia macrophylla | King | Meliaceae | 8 |
| Symphoricarpos albus | (L.) S.F.Blake | Caprifoliaceae | 8 |
| Symphoricarpos longiflorus | A.Gray | Caprifoliaceae | 8 |
| Symphoricarpos mollis | Nutt. | Caprifoliaceae | 8 |
| Symphoricarpos rotundifolius | A.Gray | Caprifoliaceae | 8 |
| Symphyotrichum falcatum | (Lindl.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum frondosum | (Nutt.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum lanceolatum | (Willd.) G.L.Nesom | Asteraceae | 8 |
| Tabebuia rosea | (Bertol.) DC. | Bignoniaceae | 8 |
| Tabernaemontana amygdalifolia | Jacq. | Apocynaceae | 8 |
| Tabernaemontana glabra | (Benth.) A.O.Simões & M.E.Endress | Apocynaceae | 8 |
| Tabernaemontana tomentosa | (Greenm.) A.O.Simões & M.E.Endress | Apocynaceae | 8 |
| Tagetes epapposa | B.L.Turner | Asteraceae | 8 |
| Tagetes erecta | L. | Asteraceae | 8 |
| Tagetes filifolia | Lag. | Asteraceae | 8 |
| Tagetes foetidissima | hort. ex DC. | Asteraceae | 8 |
| Tagetes lemmonii | A.Gray | Asteraceae | 8 |
| Tagetes lucida | Cav. | Asteraceae | 8 |
| Tagetes lunulata | Ortega | Asteraceae | 8 |
| Tagetes micrantha | Cav. | Asteraceae | 8 |
| Tagetes subulata | Cerv. | Asteraceae | 8 |
| Tagetes tenuifolia | Cav. | Asteraceae | 8 |
| Talinum aurantiacum | Engelm. | Talinaceae | 8 |
| Talinum fruticosum | (L.) Juss. | Talinaceae | 8 |
| Talinum paniculatum | (Jacq.) Gaertn. | Talinaceae | 8 |
| Talinum polygaloides | Gillies ex Arn. | Talinaceae | 8 |
| Tara cacalaco | (Bonpl.) Molinari & Sánchez Och. | Fabaceae | 8 |
| Tarenaya aculeata | (L.) Soares Neto & Roalson | Cleomaceae | 8 |
| Tauschia arguta | (Torr. & A.Gray) J.F.Macbr. | Apiaceae | 8 |
| Taxodium distichum | (L.) Rich. | Cupressaceae | 8 |
| Tecoma stans | (L.) Juss. | Bignoniaceae | 8 |
| Tephrosia palmeri | S.Watson | Fabaceae | 8 |
| Tephrosia thurberi | (Rydb.) C.E.Wood | Fabaceae | 8 |
| Tetraclea coulteri | A.Gray | Lamiaceae | 8 |
| Tetracoccus dioicus | Parry | Picrodendraceae | 8 |
| Tetracoccus hallii | Brandegee | Picrodendraceae | 8 |
| Tetradymia comosa | A.Gray | Asteraceae | 8 |
| Tetramerium nervosum | Nees | Acanthaceae | 8 |
| Tetrapteron graciliflorum | (Hook. & Arn.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Tetrapterys mexicana | Hook. & Arn. | Malpighiaceae | 8 |
| Teucrium canadense | L. | Lamiaceae | 8 |
| Teucrium depressum | Small | Lamiaceae | 8 |
| Teucrium glandulosum | Kellogg | Lamiaceae | 8 |
| Teucrium vesicarium | Mill. | Lamiaceae | 8 |
| Thalia geniculata | L. | Marantaceae | 8 |
| Thalictrum fendleri | Engelm. ex A.Gray | Ranunculaceae | 8 |
| Thalictrum polycarpum | (Torr.) S.Watson | Ranunculaceae | 8 |
| Thamnosma montana | Torr. & Frém. | Rutaceae | 8 |
| Thelesperma longipes | A.Gray | Asteraceae | 8 |
| Thelesperma megapotamicum | (Spreng.) Kuntze | Asteraceae | 8 |
| Thelypodium wrightii | A.Gray | Brassicaceae | 8 |
| Thouinia acuminata | S.Watson | Sapindaceae | 8 |
| Thouinidium decandrum | (Bonpl.) Radlk. | Sapindaceae | 8 |
| Thymophylla acerosa | (DC.) Strother | Asteraceae | 8 |
| Thymophylla concinna | (A.Gray) Strother | Asteraceae | 8 |
| Thymophylla pentachaeta | (DC.) Small | Asteraceae | 8 |
| Thymophylla setifolia | Lag. | Asteraceae | 8 |
| Thysanocarpus curvipes | Hook. | Brassicaceae | 8 |
| Thysanocarpus laciniatus | Nutt. | Brassicaceae | 8 |
| Tidestromia lanuginosa | (Nutt.) Standl. | Amaranthaceae | 8 |
| Tidestromia suffruticosa | (Torr.) Standl. | Amaranthaceae | 8 |
| Tigridia pavonia | (L.f.) Redouté | Iridaceae | 8 |
| Tilia americana | L. | Malvaceae | 8 |
| Tillandsia achyrostachys | É.Morren ex Baker | Bromeliaceae | 8 |
| Tillandsia balbisiana | Schult. & Schult.f. | Bromeliaceae | 8 |
| Tillandsia capitata | Griseb. | Bromeliaceae | 8 |
| Tillandsia caput-medusae | É.Morren | Bromeliaceae | 8 |
| Tillandsia erubescens | Schltdl. | Bromeliaceae | 8 |
| Tillandsia exserta | Fernald | Bromeliaceae | 8 |
| Tillandsia fasciculata | Sw. | Bromeliaceae | 8 |
| Tillandsia fuchsii | W.Till | Bromeliaceae | 8 |
| Tillandsia intermedia | Mez | Bromeliaceae | 8 |
| Tillandsia juncea | (Ruiz & Pav.) Poir. | Bromeliaceae | 8 |
| Tillandsia limbata | Schltdl. | Bromeliaceae | 8 |
| Tillandsia makoyana | Baker | Bromeliaceae | 8 |
| Tillandsia paucifolia | Baker | Bromeliaceae | 8 |
| Tillandsia recurvata | (L.) L. | Bromeliaceae | 8 |
| Tillandsia schiedeana | Steud. | Bromeliaceae | 8 |
| Tillandsia setacea | Sw. | Bromeliaceae | 8 |
| Tillandsia streptophylla | Scheidw. | Bromeliaceae | 8 |
| Tillandsia usneoides | (L.) L. | Bromeliaceae | 8 |
| Tinantia erecta | (Jacq.) Fenzl | Commelinaceae | 8 |
| Tinantia standleyi | Steyerm. | Commelinaceae | 8 |
| Tiquilia canescens | (DC.) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia greggii | (Torr. & A.Gray) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia palmeri | (A.Gray) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia plicata | (Torr.) A.T.Richardson | Ehretiaceae | 8 |
| Tithonia thurberi | A.Gray | Asteraceae | 8 |
| Tithonia tubaeformis | (Jacq.) Cass. | Asteraceae | 8 |
| Tomostima cuneifolia | (Nutt. ex Torr. & A.Gray) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Tomostima reptans | (Lam.) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Townsendia exscapa | (Richardson) Porter | Asteraceae | 8 |
| Toxicodendron diversilobum | (Torr. & A.Gray) Greene | Anacardiaceae | 8 |
| Toxicodendron radicans | (L.) Kuntze | Anacardiaceae | 8 |
| Toxicoscordion brevibracteatum | (M.E.Jones) R.R.Gates | Melanthiaceae | 8 |
| Toxicoscordion fremontii | (Torr.) Rydb. | Melanthiaceae | 8 |
| Toxicoscordion paniculatum | (Nutt.) Rydb. | Melanthiaceae | 8 |
| Toxicoscordion venenosum | (S.Watson) Rydb. | Melanthiaceae | 8 |
| Tradescantia commelinoides | Schult. & Schult.f. | Commelinaceae | 8 |
| Tradescantia crassifolia | Cav. | Commelinaceae | 8 |
| Tradescantia occidentalis | (Britton) Smyth | Commelinaceae | 8 |
| Tradescantia peninsularis | Brandegee | Commelinaceae | 8 |
| Tradescantia pinetorum | Greene | Commelinaceae | 8 |
| Tragia amblyodonta | (Müll.Arg.) Pax & K.Hoffm. | Euphorbiaceae | 8 |
| Tragia nepetifolia | Cav. | Euphorbiaceae | 8 |
| Tragia ramosa | Torr. | Euphorbiaceae | 8 |
| Trema micranthum | (L.) Blume | Cannabaceae | 8 |
| Trianthema portulacastrum | L. | Aizoaceae | 8 |
| Trichilia havanensis | Jacq. | Meliaceae | 8 |
| Trichilia hirta | L. | Meliaceae | 8 |
| Trichilia trifolia | L. | Meliaceae | 8 |
| Trichogalium fendleri | (A.Gray) Kadereit & Schneew. | Rubiaceae | 8 |
| Trichogalium martirense | (Dempster & Stebbins) Kadereit & Schneew. | Rubiaceae | 8 |
| Trichoptilium incisum | (A.Gray) A.Gray | Asteraceae | 8 |
| Trichospermum mexicanum | (DC.) Baill. | Malvaceae | 8 |
| Trichostema arizonicum | A.Gray | Lamiaceae | 8 |
| Trichostema lanatum | Benth. | Lamiaceae | 8 |
| Trichostema lanceolatum | Benth. | Lamiaceae | 8 |
| Trichostema parishii | Vasey | Lamiaceae | 8 |
| Trichostigma octandrum | (L.) H.Walter | Petiveriaceae | 8 |
| Tridax procumbens | L. | Asteraceae | 8 |
| Tridentopsis mutica | (Torr.) P.M.Peterson | Poaceae | 8 |
| Trifolium albopurpureum | Torr. & A.Gray | Fabaceae | 8 |
| Trifolium amabile | Kunth | Fabaceae | 8 |
| Trifolium bifidum | A.Gray | Fabaceae | 8 |
| Trifolium breweri | S.Watson | Fabaceae | 8 |
| Trifolium ciliolatum | Benth. | Fabaceae | 8 |
| Trifolium depauperatum | Desv. | Fabaceae | 8 |
| Trifolium gracilentum | Torr. & A.Gray | Fabaceae | 8 |
| Trifolium microcephalum | Pursh | Fabaceae | 8 |
| Trifolium microdon | Hook. & Arn. | Fabaceae | 8 |
| Trifolium monanthum | A.Gray | Fabaceae | 8 |
| Trifolium obtusiflorum | Hook. | Fabaceae | 8 |
| Trifolium palmeri | S.Watson | Fabaceae | 8 |
| Trifolium pinetorum | Greene | Fabaceae | 8 |
| Trifolium variegatum | Nutt. | Fabaceae | 8 |
| Trifolium willdenovii | Spreng. | Fabaceae | 8 |
| Trifolium wormskioldii | Lehm. | Fabaceae | 8 |
| Triglochin maritima | L. | Juncaginaceae | 8 |
| Triglochin scilloides | (Poir.) Mering & Kadereit | Juncaginaceae | 8 |
| Trigonospermum melampodioides | DC. | Asteraceae | 8 |
| Triodanis perfoliata | (L.) Nieuwl. | Campanulaceae | 8 |
| Triphora trianthophoros | (Sw.) Rydb. | Orchidaceae | 8 |
| Tripogandra amplexicaulis | (Klotzsch ex C.B.Clarke) Woodson | Commelinaceae | 8 |
| Tripogandra purpurascens | (S.Schauer) Handlos | Commelinaceae | 8 |
| Tripsacum dactyloides | (L.) L. | Poaceae | 8 |
| Triteleiopsis palmeri | (S.Watson) Hoover | Asparagaceae | 8 |
| Triumfetta semitriloba | Jacq. | Malvaceae | 8 |
| Trixis californica | Kellogg | Asteraceae | 8 |
| Trixis pterocaulis | B.L.Rob. & Greenm. | Asteraceae | 8 |
| Trophis racemosa | (L.) Urb. | Moraceae | 8 |
| Tropidocarpum gracile | Hook. | Brassicaceae | 8 |
| Turnera diffusa | Willd. ex Schult. | Passifloraceae | 8 |
| Turnera pumilea | L. | Passifloraceae | 8 |
| Turnera ulmifolia | L. | Passifloraceae | 8 |
| Tutunakanthus velutinus | (Schltdl.) Morillo, Liede & Meve | Apocynaceae | 8 |
| Typha angustifolia | L. | Typhaceae | 8 |
| Typha domingensis | Pers. | Typhaceae | 8 |
| Typha latifolia | L. | Typhaceae | 8 |
| Ulmus americana | L. | Ulmaceae | 8 |
| Umbellularia californica | (Hook. & Arn.) Nutt. | Lauraceae | 8 |
| Ungnadia speciosa | Endl. | Sapindaceae | 8 |
| Urbinella palmeri | Greenm. | Asteraceae | 8 |
| Urera baccifera | (L.) Gaudich. ex Wedd. | Urticaceae | 8 |
| Urera caracasana | (Jacq.) Gaudich. ex Griseb. | Urticaceae | 8 |
| Urochloa arizonica | (Scribn. & Merr.) Morrone & Zuloaga | Poaceae | 8 |
| Uropappus lindleyi | (DC.) Nutt. | Asteraceae | 8 |
| Urtica chamaedryoides | Pursh | Urticaceae | 8 |
| Urtica gracilis | Aiton | Urticaceae | 8 |
| Urvillea ulmacea | Kunth | Sapindaceae | 8 |
| Utricularia gibba | L. | Lentibulariaceae | 8 |
| Utricularia livida | E.Mey. | Lentibulariaceae | 8 |
| Utricularia macrorhiza | Leconte | Lentibulariaceae | 8 |
| Vaccinium stenophyllum | Steud. | Ericaceae | 8 |
| Vachellia campeachiana | (Mill.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia constricta | (Benth.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia farnesiana | (L.) Wight & Arn. | Fabaceae | 8 |
| Vachellia hindsii | (Benth.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia macracantha | (Humb. & Bonpl. ex Willd.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia pacensis | (Rudd & A.M.Carter) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia pennatula | (Schltdl. & Cham.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia rigidula | (Benth.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia schaffneri | (S.Watson) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia vernicosa | (Britton & Rose) Seigler & Ebinger | Fabaceae | 8 |
| Valeriana ciliosa | (Greene) Byng & Christenh. | Caprifoliaceae | 8 |
| Valeriana edulis | Nutt. | Caprifoliaceae | 8 |
| Valeriana sorbifolia | Kunth | Caprifoliaceae | 8 |
| Vallesia glabra | (Cav.) Link | Apocynaceae | 8 |
| Varronia curassavica | Jacq. | Cordiaceae | 8 |
| Varronia spinescens | (L.) Borhidi | Cordiaceae | 8 |
| Venegasia carpesioides | DC. | Asteraceae | 8 |
| Veratrum californicum | Durand | Melanthiaceae | 8 |
| Verbena bipinnatifida | (Nutt.) Schauer | Verbenaceae | 8 |
| Verbena bracteata | Cav. ex Lag. & Rodr. | Verbenaceae | 8 |
| Verbena canescens | Kunth | Verbenaceae | 8 |
| Verbena carolina | L. | Verbenaceae | 8 |
| Verbena chiricahensis | (Umber) Moldenke | Verbenaceae | 8 |
| Verbena elegans | Kunth | Verbenaceae | 8 |
| Verbena gooddingii | Briq. | Verbenaceae | 8 |
| Verbena halei | Small | Verbenaceae | 8 |
| Verbena lasiostachys | Link | Verbenaceae | 8 |
| Verbena litoralis | Kunth | Verbenaceae | 8 |
| Verbena macdougalii | A.Heller | Verbenaceae | 8 |
| Verbena menthifolia | Benth. | Verbenaceae | 8 |
| Verbena neomexicana | (A.Gray) Briq. | Verbenaceae | 8 |
| Verbena perennis | Wooton | Verbenaceae | 8 |
| Verbena plicata | Greene | Verbenaceae | 8 |
| Verbena pumila | Rydb. | Verbenaceae | 8 |
| Verbena scabra | Vahl | Verbenaceae | 8 |
| Verbena simplex | Lehm. | Verbenaceae | 8 |
| Verbena xutha | Lehm. | Verbenaceae | 8 |
| Verbesina dissita | A.Gray | Asteraceae | 8 |
| Verbesina fastigiata | B.L.Rob. & Greenm. | Asteraceae | 8 |
| Verbesina longifolia | A.Gray | Asteraceae | 8 |
| Verbesina oligantha | B.L.Rob. | Asteraceae | 8 |
| Verbesina oncophora | B.L.Rob. & Seaton | Asteraceae | 8 |
| Verbesina parviflora | S.F.Blake | Asteraceae | 8 |
| Verbesina turbacensis | Kunth | Asteraceae | 8 |
| Vernonanthura patens | (Kunth) H.Rob. | Asteraceae | 8 |
| Vernonia paniculata | DC. | Asteraceae | 8 |
| Veronica americana | (Raf.) Schwein. ex Benth. | Plantaginaceae | 8 |
| Veronica peregrina | L. | Plantaginaceae | 8 |
| Veronica serpyllifolia | L. | Plantaginaceae | 8 |
| Vesper multinervatus | (J.M.Coult. & Rose) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vicia americana | Muhl. ex Willd. | Fabaceae | 8 |
| Vicia hassei | S.Watson | Fabaceae | 8 |
| Vicia ludoviciana | Nutt. | Fabaceae | 8 |
| Vicia pulchella | Kunth | Fabaceae | 8 |
| Viguiera dentata | (Cav.) Spreng. | Asteraceae | 8 |
| Viguiera lanata | A.Gray | Asteraceae | 8 |
| Viola adunca | Sm. | Violaceae | 8 |
| Viola douglasii | Steud. | Violaceae | 8 |
| Viola lobata | Benth. | Violaceae | 8 |
| Viola nephrophylla | Greene | Violaceae | 8 |
| Viola pedunculata | Torr. & A.Gray | Violaceae | 8 |
| Viola purpurea | Kellogg | Violaceae | 8 |
| Viscainoa geniculata | (Kellogg) Greene | Zygophyllaceae | 8 |
| Vitex mollis | Kunth | Lamiaceae | 8 |
| Vitex pyramidata | B.L.Rob. | Lamiaceae | 8 |
| Vitis arizonica | Engelm. | Vitaceae | 8 |
| Vitis cinerea | (Engelm.) Millardet | Vitaceae | 8 |
| Vitis rotundifolia | Michx. | Vitaceae | 8 |
| Vitis tiliifolia | Humb. & Bonpl. ex Schult. | Vitaceae | 8 |
| Waltheria acuminata | Rose | Malvaceae | 8 |
| Waltheria indica | L. | Malvaceae | 8 |
| Washingtonia filifera | (Rafarin) H.Wendl. ex de Bary | Arecaceae | 8 |
| Wedelia acapulcensis | Kunth | Asteraceae | 8 |
| Wigandia urens | (Ruiz & Pav.) Kunth | Namaceae | 8 |
| Wissadula amplissima | (L.) R.E.Fr. | Malvaceae | 8 |
| Wolffia columbiana | H.Karst. | Araceae | 8 |
| Woodsia phillipsii | Windham | Woodsiaceae | 8 |
| Woodwardia fimbriata | Sm. | Blechnaceae | 8 |
| Xanthisma gracile | (Nutt.) D.R.Morgan & R.L.Hartm. | Asteraceae | 8 |
| Xanthisma junceum | (Greene) D.R.Morgan & R.L.Hartm. | Asteraceae | 8 |
| Xanthisma spinulosum | (Pursh) D.R.Morgan & R.L.Hartm. | Asteraceae | 8 |
| Xanthium orientale | L. | Asteraceae | 8 |
| Xanthium spinosum | L. | Asteraceae | 8 |
| Xanthocephalum gymnospermoides | (A.Gray) Benth. & Hook.f. | Asteraceae | 8 |
| Xanthosoma wendlandii | (Schott) Standl. | Araceae | 8 |
| Xylococcus bicolor | Nutt. | Ericaceae | 8 |
| Xylorhiza orcuttii | Greene | Asteraceae | 8 |
| Xylosma flexuosa | (Kunth) Hemsl. | Salicaceae | 8 |
| Xylosma intermedia | (Seem.) Triana & Planch. | Salicaceae | 8 |
| Xylothamia diffusa | (Benth.) G.L.Nesom | Asteraceae | 8 |
| Yabea microcarpa | Koso-Pol. | Apiaceae | 8 |
| Yucca baccata | Torr. | Asparagaceae | 8 |
| Yucca brevifolia | Engelm. | Asparagaceae | 8 |
| Yucca capensis | L.W.Lenz | Asparagaceae | 8 |
| Yucca elata | (Engelm.) Engelm. | Asparagaceae | 8 |
| Yucca madrensis | Gentry | Asparagaceae | 8 |
| Yucca schidigera | Roezl ex Ortgies | Asparagaceae | 8 |
| Yucca valida | Brandegee | Asparagaceae | 8 |
| Zaluzania triloba | (Ortega) Pers. | Asteraceae | 8 |
| Zannichellia palustris | L. | Potamogetonaceae | 8 |
| Zanthoxylum arborescens | Rose | Rutaceae | 8 |
| Zanthoxylum fagara | Sarg. | Rutaceae | 8 |
| Zanthoxylum schreberi | (J.F.Gmel.) Reynel | Rutaceae | 8 |
| Zapoteca formosa | (Kunth) H.M.Hern. | Fabaceae | 8 |
| Zeltnera arizonica | (A.Gray) G.Mans. | Gentianaceae | 8 |
| Zeltnera davyi | (Jeps.) G.Mans. | Gentianaceae | 8 |
| Zeltnera exaltata | (Griseb.) G.Mans. | Gentianaceae | 8 |
| Zeltnera venusta | (A.Gray) G.Mans. | Gentianaceae | 8 |
| Zinnia acerosa | (DC.) A.Gray | Asteraceae | 8 |
| Zinnia elegans | Jacq. | Asteraceae | 8 |
| Zinnia grandiflora | Nutt. | Asteraceae | 8 |
| Zinnia juniperifolia | A.Gray | Asteraceae | 8 |
| Zinnia maritima | Kunth | Asteraceae | 8 |
| Zinnia peruviana | (L.) L. | Asteraceae | 8 |
| Zinnia zinnioides | (Kunth) Olorode & A.M.Torres | Asteraceae | 8 |
| Zizania palustris | L. | Poaceae | 8 |
| Zornia reticulata | Sm. | Fabaceae | 8 |
| Zostera marina | L. | Zosteraceae | 8 |
| Zuloagaea bulbosa | (Kunth) Bess | Poaceae | 8 |
| Zygophyllum laeve | (Standl.) Christenh. & Byng | Zygophyllaceae | 8 |
| Zygophyllum pachyacanthum | (Rydb.) Christenh. & Byng | Zygophyllaceae | 8 |
| Abutilon californicum | Benth. | Malvaceae | 7 |
| Achimenes flava | C.V.Morton | Gesneriaceae | 7 |
| Adelia obovata | Wiggins & Rollins | Euphorbiaceae | 7 |
| Agalinis peduncularis | (Benth.) Pennell | Orobanchaceae | 7 |
| Aldama brandegeei | (A.M.Carter) E.E.Schill. & Panero | Asteraceae | 7 |
| Aphananthe monoica | (Hemsl.) J.-F.Leroy | Cannabaceae | 7 |
| Aquilegia skinneri | Hook. | Ranunculaceae | 7 |
| Arisaema macrospathum | Benth. | Araceae | 7 |
| Aristolochia pringlei | Rose | Aristolochiaceae | 7 |
| Asclepias mexicana | Cav. | Apocynaceae | 7 |
| Astragalus fastidius | (Kellogg) M.E.Jones | Fabaceae | 7 |
| Astragalus pringlei | S.Watson | Fabaceae | 7 |
| Baccharis bigelovii | A.Gray | Asteraceae | 7 |
| Bajacalia moranii | B.L.Turner | Asteraceae | 7 |
| Bernardia mexicana | (Hook. & Arn.) Müll.Arg. | Euphorbiaceae | 7 |
| Boechera xylopoda | Windham & Al-Shehbaz | Brassicaceae | 7 |
| Boerhavia spicata | Choisy | Nyctaginaceae | 7 |
| Bouteloua radicosa | (E.Fourn.) Griffiths | Poaceae | 7 |
| Bromus marginatus | Nees ex Steud. | Poaceae | 7 |
| Camissoniopsis confusa | (P.H.Raven) W.L.Wagner & Hoch | Onagraceae | 7 |
| Casearia aculeata | Jacq. | Salicaceae | 7 |
| Centrosema sagittatum | (Humb. & Bonpl. ex Willd.) Brandegee | Fabaceae | 7 |
| Chaetymenia peduncularis | Hook. & Arn. | Asteraceae | 7 |
| Christella hispidula | (Decne.) Holttum | Thelypteridaceae | 7 |
| Chrysanthellum indicum | DC. | Asteraceae | 7 |
| Condalia mexicana | Schltdl. | Rhamnaceae | 7 |
| Condea tephrodes | (A.Gray) Harley & J.F.B.Pastore | Lamiaceae | 7 |
| Cosmos palmeri | B.L.Rob. | Asteraceae | 7 |
| Crepis runcinata | (E.James) Torr. & A.Gray | Asteraceae | 7 |
| Croton culiacanensis | Croizat | Euphorbiaceae | 7 |
| Croton pseudoniveus | Lundell | Euphorbiaceae | 7 |
| Cryptantha ganderi | I.M.Johnst. | Boraginaceae | 7 |
| Cyperus pallidicolor | (Kük.) G.C.Tucker | Cyperaceae | 7 |
| Dalea filiformis | A.Gray | Fabaceae | 7 |
| Dioon tomasellii | De Luca, Sabato & Vázq.Torres | Zamiaceae | 7 |
| Echinocereus dasyacanthus | Engelm. | Cactaceae | 7 |
| Elionurus barbiculmis | Hack. ex Scribn. | Poaceae | 7 |
| Encelia palmeri | Vasey & Rose | Asteraceae | 7 |
| Eriochloa acuminata | (J.Presl) Kunth | Poaceae | 7 |
| Eriogonum pondii | Greene | Polygonaceae | 7 |
| Erythranthe exigua | (A.Gray) G.L.Nesom & N.S.Fraga | Phrymaceae | 7 |
| Euphorbia pondii | Millsp. | Euphorbiaceae | 7 |
| Frangula betulifolia | (Greene) Grubov | Rhamnaceae | 7 |
| Galphimia paniculata | Bartl. | Malpighiaceae | 7 |
| Gnaphaliothamnus salicifolius | (Bertol.) G.L.Nesom | Asteraceae | 7 |
| Gomphrena nitida | Rothr. | Amaranthaceae | 7 |
| Habenaria jaliscana | S.Watson | Orchidaceae | 7 |
| Hesperocyparis montana | (Wiggins) Bartel & R.A.Price | Cupressaceae | 7 |
| Hibiscus biseptus | S.Watson | Malvaceae | 7 |
| Ipomoea setosa | Ker Gawl. | Convolvulaceae | 7 |
| Juncus oxymeris | Engelm. | Juncaceae | 7 |
| Lasianthaea palmeri | (Greenm.) K.M.Becker | Asteraceae | 7 |
| Lastarriaea chilensis | J.Rémy | Polygonaceae | 7 |
| Leptosiphon melingii | (Wiggins) J.M.Porter & L.A.Johnson | Polemoniaceae | 7 |
| Linanthus bigelovii | (A.Gray) Greene | Polemoniaceae | 7 |
| Lonchocarpus guatemalensis | Benth. | Fabaceae | 7 |
| Machaonia erythrocarpa | (Standl.) Borhidi | Rubiaceae | 7 |
| Manihot aesculifolia | (Kunth) Pohl | Euphorbiaceae | 7 |
| Marina orcuttii | (S.Watson) Barneby | Fabaceae | 7 |
| Mariosousa millefolia | (S.Watson) Seigler & Ebinger | Fabaceae | 7 |
| Matricaria occidentalis | Greene | Asteraceae | 7 |
| Melampodium longicorne | A.Gray | Asteraceae | 7 |
| Miconia submontana | (Rose ex Gleason) Michelang. | Melastomataceae | 7 |
| Microseris elegans | Greene ex A.Gray | Asteraceae | 7 |
| Monardella linoides | A.Gray | Lamiaceae | 7 |
| Moussonia jaliscana | (S.Watson) D.L.Denham ex Ram.-Roa | Gesneriaceae | 7 |
| Nicolletia edwardsii | A.Gray | Asteraceae | 7 |
| Ophioglossum nudicaule | L.f. | Ophioglossaceae | 7 |
| Philodendron dressleri | G.S.Bunting | Araceae | 7 |
| Phyllonoma laticuspis | (Turcz.) Engl. | Phyllonomaceae | 7 |
| Physalis caudella | Standl. | Solanaceae | 7 |
| Pinguicula crenatiloba | A.DC. | Lentibulariaceae | 7 |
| Plantago linearis | Kunth | Plantaginaceae | 7 |
| Populus mexicana | Wesm. | Salicaceae | 7 |
| Pseudognaphalium viscosum | (Kunth) Anderb. | Asteraceae | 7 |
| Psychotria horizontalis | Sw. | Rubiaceae | 7 |
| Quercus crassipes | Bonpl. | Fagaceae | 7 |
| Randia cookii | Standl. | Rubiaceae | 7 |
| Rhus lentii | Kellogg | Anacardiaceae | 7 |
| Ruehssia lanata | (Paul G.Wilson) L.O.Alvarado | Apocynaceae | 7 |
| Ruellia intermedia | Leonard | Acanthaceae | 7 |
| Rumex orthoneurus | Rech.f. | Polygonaceae | 7 |
| Sageretia wrightii | S.Watson | Rhamnaceae | 7 |
| Senna quinquangulata | (Rich.) H.S.Irwin & Barneby | Fabaceae | 7 |
| Serjania cardiospermoides | Schltdl. & Cham. | Sapindaceae | 7 |
| Serjania spinosa | (Radlk.) Ferrucci & V.W.Steinm. | Sapindaceae | 7 |
| Sida neomexicana | A.Gray | Malvaceae | 7 |
| Sisyrinchium pringlei | B.L.Rob. & Greenm. | Iridaceae | 7 |
| Sphaeralcea axillaris | S.Watson | Malvaceae | 7 |
| Stachys tenerrima | Epling | Lamiaceae | 7 |
| Struthanthus interruptus | G.Don | Loranthaceae | 7 |
| Talayotea trachyantha | (Greenm.) L.O.Alvarado | Apocynaceae | 7 |
| Tephrosia multifolia | Rose | Fabaceae | 7 |
| Tephrosia nicaraguensis | Oerst. | Fabaceae | 7 |
| Trichocoronis wrightii | A.Gray | Asteraceae | 7 |
| Viola barroetana | Schaffn. ex Hemsl. | Violaceae | 7 |
| Woodwardia spinulosa | M.Martens & Galeotti | Blechnaceae | 7 |
| Zapoteca portoricensis | (Jacq.) H.M.Hern. | Fabaceae | 7 |
| Ageratina vernalis | (Vatke & Kurtz) R.M.King & H.Rob. | Asteraceae | 6 |
| Allium glandulosum | Link & Otto | Amaryllidaceae | 6 |
| Alloispermum scabrum | (Lag.) H.Rob. | Asteraceae | 6 |
| Anthephora hermaphrodita | (L.) Kuntze | Poaceae | 6 |
| Arenaria bourgaei | Hemsl. | Caryophyllaceae | 6 |
| Asemeia apopetala | (Brandegee) J.F.B.Pastore & J.R.Abbott | Polygalaceae | 6 |
| Atriplex cristata | Humb. & Bonpl. ex Willd. | Chenopodiaceae | 6 |
| Berberis claireae | R.C.Moran | Berberidaceae | 6 |
| Berberis moranensis | Hebenstr. & Ludw. ex Schult. & Schult.f. | Berberidaceae | 6 |
| Bonellia nervosa | (C.Presl) B.Ståhl & Källersjö | Primulaceae | 6 |
| Bouchea dissecta | S.Watson | Verbenaceae | 6 |
| Bouteloua diversispicula | Columbus | Poaceae | 6 |
| Brahea calcarea | Liebm. | Arecaceae | 6 |
| Bromus pseudolaevipes | Wagnon | Poaceae | 6 |
| Buchnera obliqua | Benth. | Orobanchaceae | 6 |
| Canavalia brasiliensis | Mart. ex Benth. | Fabaceae | 6 |
| Castilleja nervata | Eastw. | Orobanchaceae | 6 |
| Clethra hartwegii | Britton | Clethraceae | 6 |
| Cochemiea capensis | (H.E.Gates) Doweld | Cactaceae | 6 |
| Colubrina heteroneura | (Griseb.) Standl. | Rhamnaceae | 6 |
| Cosmos concolor | Sherff | Asteraceae | 6 |
| Crossopetalum parviflorum | (Hemsl.) Lundell | Celastraceae | 6 |
| Crotalaria longirostrata | Hook. & Arn. | Fabaceae | 6 |
| Croton argenteus | L. | Euphorbiaceae | 6 |
| Cuphea lanceolata | W.T.Aiton | Lythraceae | 6 |
| Cuscuta veatchii | Brandegee | Convolvulaceae | 6 |
| Cylindropuntia cedrosensis | Rebman | Cactaceae | 6 |
| Cyperus amabilis | Vahl | Cyperaceae | 6 |
| Descurainia adenophora | (Wooton & Standl.) O.E.Schulz | Brassicaceae | 6 |
| Desmodium densiflorum | Hemsl. | Fabaceae | 6 |
| Distimake palmeri | (S.Watson) A.R.Simões & Staples | Convolvulaceae | 6 |
| Dudleya candida | Britton | Crassulaceae | 6 |
| Dudleya linearis | Britton & Rose | Crassulaceae | 6 |
| Dudleya pauciflora | Rose | Crassulaceae | 6 |
| Echinocactus horizonthalonius | Lem. | Cactaceae | 6 |
| Echinopterys eglandulosa | (A.Juss.) Small | Malpighiaceae | 6 |
| Eriogonum intricatum | Benth. | Polygonaceae | 6 |
| Euphorbia bracteata | Jacq. | Euphorbiaceae | 6 |
| Euploca fruticosa | (L.) J.I.M.Melo & Semir | Heliotropiaceae | 6 |
| Evolvulus cardiophyllus | Schltdl. | Convolvulaceae | 6 |
| Ferocactus chrysacanthus | (Orcutt) Britton & Rose | Cactaceae | 6 |
| Gayophytum diffusum | Torr. & A.Gray | Onagraceae | 6 |
| Graptopetalum rusbyi | Rose | Crassulaceae | 6 |
| Halenia palmeri | A.Gray | Gentianaceae | 6 |
| Halodule wrightii | Asch. | Cymodoceaceae | 6 |
| Heteropterys laurifolia | (L.) A.Juss. | Malpighiaceae | 6 |
| Heuchera mexicana | W.Schaffn. ex Rydb. | Saxifragaceae | 6 |
| Hypoxis mexicana | Schult. & Schult.f. | Hypoxidaceae | 6 |
| Imperata brevifolia | Vasey | Poaceae | 6 |
| Indigofera sphaerocarpa | A.Gray | Fabaceae | 6 |
| Iostephane madrensis | (S.Watson) Strother | Asteraceae | 6 |
| Justicia carthaginensis | Jacq. | Acanthaceae | 6 |
| Karwinskia calderonii | Standl. | Rhamnaceae | 6 |
| Lasianthaea macrocephala | (Hook. & Arn.) K.M.Becker | Asteraceae | 6 |
| Laubertia contorta | (M.Martens & Galeotti) Woodson | Apocynaceae | 6 |
| Lepidium latipes | Hook. | Brassicaceae | 6 |
| Leucaena lanceolata | S.Watson | Fabaceae | 6 |
| Lonchocarpus lanceolatus | Benth. | Fabaceae | 6 |
| Lycianthes dejecta | (Fernald) Bitter | Solanaceae | 6 |
| Lycianthes surotatensis | Gentry | Solanaceae | 6 |
| Mandevilla hesperia | (I.M.Johnst.) A.O.Simões, Kin.-Gouv. & M.E.Endress | Apocynaceae | 6 |
| Marina interstes | Barneby | Fabaceae | 6 |
| Marsilea mollis | B.L.Rob. & Fernald | Marsileaceae | 6 |
| Metastelma pringlei | A.Gray | Apocynaceae | 6 |
| Microchloa kunthii | Desv. | Poaceae | 6 |
| Micropleura renifolia | Lag. | Apiaceae | 6 |
| Mirabilis triflora | Benth. | Nyctaginaceae | 6 |
| Opuntia tapona | Engelm. ex J.M.Coult. | Cactaceae | 6 |
| Penstemon wislizeni | (A.Gray) Straw | Plantaginaceae | 6 |
| Phacelia scariosa | Brandegee | Hydrophyllaceae | 6 |
| Phalaris angusta | Nees ex Trin. | Poaceae | 6 |
| Plantago argyrea | E.Morris | Plantaginaceae | 6 |
| Polygala xanti | A.Gray | Polygalaceae | 6 |
| Polygonum ramosissimum | Michx. | Polygonaceae | 6 |
| Prockia crucis | P.Browne ex L. | Salicaceae | 6 |
| Quercus glaucescens | Bonpl. | Fagaceae | 6 |
| Quercus scytophylla | Liebm. | Fagaceae | 6 |
| Russelia retrorsa | Greene | Plantaginaceae | 6 |
| Sageretia elegans | (Kunth) Brongn. | Rhamnaceae | 6 |
| Saltugilia caruifolia | (Abrams) L.A.Johnson | Polemoniaceae | 6 |
| Salvia platycheila | A.Gray | Lamiaceae | 6 |
| Sapium macrocarpum | Müll.Arg. | Euphorbiaceae | 6 |
| Schoepfia californica | Brandegee | Schoepfiaceae | 6 |
| Schultesia guianensis | (Aubl.) Malme | Gentianaceae | 6 |
| Seymeria bipinnatisecta | Seem. | Orobanchaceae | 6 |
| Sigmoidotropis speciosa | (Kunth) A.Delgado | Fabaceae | 6 |
| Stevia caracasana | DC. | Asteraceae | 6 |
| Stevia jorullensis | Kunth | Asteraceae | 6 |
| Suberogerens cyclophylla | (Standl.) Morillo | Apocynaceae | 6 |
| Tiquilia cuspidata | (I.M.Johnst.) A.T.Richardson | Ehretiaceae | 6 |
| Tridax platyphylla | B.L.Rob. | Asteraceae | 6 |
| Trixis angustifolia | DC. | Asteraceae | 6 |
| Trixis hyposericea | S.Watson | Asteraceae | 6 |
| Urostephanus gonoloboides | B.L.Rob. & Greenm. | Apocynaceae | 6 |
| Varronia bullata | L. | Cordiaceae | 6 |
| Vasconcellea cauliflora | (Jacq.) A.DC. | Caricaceae | 6 |
| Verbesina longipes | Hemsl. | Asteraceae | 6 |
| Vittaria graminifolia | Kaulf. | Pteridaceae | 6 |
| Wedelia mexicana | (Sch.Bip.) McVaugh | Asteraceae | 6 |
| Woodsia plummerae | Lemmon | Woodsiaceae | 6 |
| Zapoteca media | (M.Martens & Galeotti) H.M.Hern. | Fabaceae | 6 |
| Zinnia angustifolia | Kunth | Asteraceae | 6 |
| Abies durangensis | Martínez | Pinaceae | 5 |
| Aeschynomene rudis | Benth. | Fabaceae | 5 |
| Agave maximiliana | Baker | Asparagaceae | 5 |
| Agave singuliflora | (S.Watson) A.Berger | Asparagaceae | 5 |
| Alchemilla aphanoides | Mutis ex L.f. | Rosaceae | 5 |
| Anoda palmata | Fryxell | Malvaceae | 5 |
| Argemone gracilenta | Greene | Papaveraceae | 5 |
| Aristida havardii | Vasey | Poaceae | 5 |
| Aristida schiedeana | Trin. & Rupr. | Poaceae | 5 |
| Aristolochia monticola | Brandegee | Aristolochiaceae | 5 |
| Arracacia atropurpurea | Benth. & Hook.f. ex Hemsl. | Apiaceae | 5 |
| Asemeia violacea | (Aubl.) J.F.B.Pastore & J.R.Abbott | Polygalaceae | 5 |
| Asplenium sessilifolium | Desv. | Aspleniaceae | 5 |
| Atriplex truncata | (Torr. ex S.Watson) A.Gray | Chenopodiaceae | 5 |
| Bastardiastrum gracile | (Hochr.) D.M.Bates | Malvaceae | 5 |
| Bidens angustissima | Kunth | Asteraceae | 5 |
| Bidens riparia | Kunth | Asteraceae | 5 |
| Blechnum polypodioides | Raddi | Blechnaceae | 5 |
| Bletia parva | Sosa & M.W.Chase | Orchidaceae | 5 |
| Bothriochloa springfieldii | (Gould) Parodi | Poaceae | 5 |
| Buddleja parviflora | Kunth | Scrophulariaceae | 5 |
| Bunchosia biocellata | Schltdl. | Malpighiaceae | 5 |
| Bursera glabrifolia | (Kunth) Engl. | Burseraceae | 5 |
| Bursera laxiflora | S.Watson | Burseraceae | 5 |
| Bursera rupicola | León de la Luz | Burseraceae | 5 |
| Camissoniopsis intermedia | (P.H.Raven) W.L.Wagner & Hoch | Onagraceae | 5 |
| Carex ultra | L.H.Bailey | Cyperaceae | 5 |
| Carphochaete wislizeni | A.Gray | Asteraceae | 5 |
| Casearia nitida | (L.) Jacq. | Salicaceae | 5 |
| Castilleja bryantii | Brandegee | Orobanchaceae | 5 |
| Chenopodium neomexicanum | Standl. | Chenopodiaceae | 5 |
| Chorizanthe polygonoides | Torr. & A.Gray | Polygonaceae | 5 |
| Cladocolea inconspicua | (Benth.) Kuijt | Loranthaceae | 5 |
| Coccoloba barbadensis | Jacq. | Polygonaceae | 5 |
| Cochemiea maritima | G.E.Linds. | Cactaceae | 5 |
| Crotalaria maypurensis | Kunth | Fabaceae | 5 |
| Croton alamosanus | Rose | Euphorbiaceae | 5 |
| Crusea wrightii | A.Gray | Rubiaceae | 5 |
| Cryosophila nana | (Kunth) Blume | Arecaceae | 5 |
| Cryptantha muricata | (Hook. & Arn.) A.Nelson & J.F.Macbr. | Boraginaceae | 5 |
| Cucurbita cordata | S.Watson | Cucurbitaceae | 5 |
| Cuscuta chinensis | Lam. | Convolvulaceae | 5 |
| Cuscuta salina | Engelm. | Convolvulaceae | 5 |
| Cyperus dioicus | I.M.Johnst. | Cyperaceae | 5 |
| Cyperus mutisii | (Kunth) Andersson | Cyperaceae | 5 |
| Dalea tomentosa | (Cav.) Willd. | Fabaceae | 5 |
| Deinandra streetsii | (A.Gray) B.G.Baldwin | Asteraceae | 5 |
| Descurainia obtusa | (Greene) O.E.Schulz | Brassicaceae | 5 |
| Dianthera candelariae | (Oerst.) Hemsl. | Acanthaceae | 5 |
| Digitaria pubiflora | (Vasey) Wipff | Poaceae | 5 |
| Dioscorea carpomaculata | O.Téllez & B.G.Schub. | Dioscoreaceae | 5 |
| Drypetes gentryi | Monach. | Putranjivaceae | 5 |
| Dudleya acuminata | Rose | Crassulaceae | 5 |
| Echinocereus rigidissimus | (Engelm.) Rose | Cactaceae | 5 |
| Echinopepon racemosus | (Steud.) C.Jeffrey | Cucurbitaceae | 5 |
| Elymus arizonicus | (Scribn. & J.G.Sm.) Gould | Poaceae | 5 |
| Eriogonum atrorubens | Engelm. | Polygonaceae | 5 |
| Euphorbia bilobata | Engelm. | Euphorbiaceae | 5 |
| Euploca wigginsii | (I.M.Johnst.) J.I.M.Melo | Heliotropiaceae | 5 |
| Fimbristylis decipiens | Kral | Cyperaceae | 5 |
| Grusonia marenae | (S.H.Parsons) E.F.Anderson | Cactaceae | 5 |
| Guarea glabra | Vahl | Meliaceae | 5 |
| Gutierrezia wrightii | A.Gray | Asteraceae | 5 |
| Iresine angustifolia | Euphrasén | Amaranthaceae | 5 |
| Karwinskia parvifolia | Rose | Rhamnaceae | 5 |
| Klaprothia fasciculata | (C.Presl) Poston | Loasaceae | 5 |
| Malvastrum bicuspidatum | (S.Watson) Rose | Malvaceae | 5 |
| Marina scopa | Barneby | Fabaceae | 5 |
| Melampodium microcephalum | Less. | Asteraceae | 5 |
| Monardella stoneana | Elvin & A.C.Sanders | Lamiaceae | 5 |
| Muhlenbergia dubia | E.Fourn. | Poaceae | 5 |
| Nama coulteri | A.Gray | Namaceae | 5 |
| Nemacladus longiflorus | A.Gray | Campanulaceae | 5 |
| Nolina palmeri | S.Watson | Asparagaceae | 5 |
| Notholaena grayi | Davenp. | Pteridaceae | 5 |
| Oenothera hispida | (Benth.) W.L.Wagner, Hoch & Zarucchi | Onagraceae | 5 |
| Orobanche parishii | (Jeps.) Heckard | Orobanchaceae | 5 |
| Parthenice mollis | A.Gray | Asteraceae | 5 |
| Passiflora fruticosa | Killip | Passifloraceae | 5 |
| Penstemon stenophyllus | A.Gray | Plantaginaceae | 5 |
| Persicaria hispida | (Kunth) M.Gómez | Polygonaceae | 5 |
| Phacelia mutabilis | Greene | Hydrophyllaceae | 5 |
| Phyllanthus elsiae | Urb. | Phyllanthaceae | 5 |
| Pilosocereus alensis | (F.A.C.Weber) Byles & G.D.Rowley | Cactaceae | 5 |
| Pinguicula lilacina | Schltdl. & Cham. | Lentibulariaceae | 5 |
| Plectocephalus rothrockii | (Greenm.) D.J.N.Hind | Asteraceae | 5 |
| Pleopeltis furfuracea | (Schltdl. & Cham.) A.R.Sm. & Tejero | Polypodiaceae | 5 |
| Pleopeltis thyssanolepis | (A.Braun ex Klotzsch) E.G.Andrews & Windham | Polypodiaceae | 5 |
| Pleurothallis quadrifida | (Lex.) Lindl. | Orchidaceae | 5 |
| Pseudabutilon umbellatum | (L.) Fryxell | Malvaceae | 5 |
| Pseudognaphalium inornatum | (DC.) Anderb. | Asteraceae | 5 |
| Randia tetracantha | (Cav.) DC. | Rubiaceae | 5 |
| Rourea glabra | Kunth | Connaraceae | 5 |
| Ruehssia edulis | (S.Watson) L.O.Alvarado | Apocynaceae | 5 |
| Sabal uresana | Trel. | Arecaceae | 5 |
| Sabdariffa costata | (A.Rich.) M.M.Hanes & R.L.Barrett | Malvaceae | 5 |
| Sabdariffa uncinella | (Moc. & Sessé ex DC.) M.M.Hanes & R.L.Barrett | Malvaceae | 5 |
| Sapranthus violaceus | (Dunal) Saff. | Annonaceae | 5 |
| Scutellaria hispidula | B.L.Rob. | Lamiaceae | 5 |
| Senna nicaraguensis | (Benth.) H.S.Irwin & Barneby | Fabaceae | 5 |
| Setaria palmeri | Henrard | Poaceae | 5 |
| Sida glabra | Mill. | Malvaceae | 5 |
| Sideroxylon cartilagineum | (Cronquist) T.D.Penn. | Sapotaceae | 5 |
| Sideroxylon occidentale | (Hemsl.) T.D.Penn. | Sapotaceae | 5 |
| Silene thurberi | S.Watson | Caryophyllaceae | 5 |
| Spermacoce suaveolens | (G.Mey.) Kuntze | Rubiaceae | 5 |
| Sphaeralcea orcuttii | Rose | Malvaceae | 5 |
| Stevia micrantha | Lag. | Asteraceae | 5 |
| Tectaria mexicana | (Fée) C.V.Morton | Tectariaceae | 5 |
| Ternstroemia lineata | DC. | Pentaphylacaceae | 5 |
| Tetracoccus capensis | (I.M.Johnst.) Croizat | Picrodendraceae | 5 |
| Tillandsia polystachia | (L.) L. | Bromeliaceae | 5 |
| Tinantia macrophylla | S.Watson | Commelinaceae | 5 |
| Trichosalpinx blaisdellii | (S.Watson) Luer | Orchidaceae | 5 |
| Trixis michuacana | Lex. | Asteraceae | 5 |
| Uniola pittieri | Hack. | Poaceae | 5 |
| Vailia anomala | (Brandegee) W.D.Stevens | Apocynaceae | 5 |
| Viola grahamii | Benth. | Violaceae | 5 |
| Waltheria preslii | Walp. | Malvaceae | 5 |
| Ximenia parviflora | Benth. | Olacaceae | 5 |
| Xylosma chiapensis | Lundell | Salicaceae | 5 |
| Adenophyllum anomalum | (M.L.Canby & Rose) Strother | Asteraceae | 4 |
| Adenophyllum porophyllum | (Cav.) Hemsl. | Asteraceae | 4 |
| Agave datylio | F.A.C.Weber | Asparagaceae | 4 |
| Agave planifolia | S.Watson | Asparagaceae | 4 |
| Aldama glomerata | (Brandegee) E.E.Schill. & Panero | Asteraceae | 4 |
| Aloysia sonorensis | Moldenke | Verbenaceae | 4 |
| Andrachne microphylla | (Lam.) Baill. | Phyllanthaceae | 4 |
| Antigonon flavescens | S.Watson | Polygonaceae | 4 |
| Archibaccharis schiedeana | (Benth.) J.D.Jacks. | Asteraceae | 4 |
| Asclepias mirifica | Woodson | Apocynaceae | 4 |
| Astragalus harbisonii | Barneby | Fabaceae | 4 |
| Athyrium dombeyi | Desv. | Athyriaceae | 4 |
| Bouteloua simplex | Lag. | Poaceae | 4 |
| Bouvardia multiflora | (Cav.) Schult. & Schult.f. | Rubiaceae | 4 |
| Brickellia lemmonii | A.Gray | Asteraceae | 4 |
| Brickellia venosa | B.L.Rob. | Asteraceae | 4 |
| Calliandra peninsularis | Rose | Fabaceae | 4 |
| Calliandra tergemina | (L.) Benth. | Fabaceae | 4 |
| Canavalia hirsutissima | J.D.Sauer | Fabaceae | 4 |
| Chamaecrista diphylla | (L.) Greene | Fabaceae | 4 |
| Chaptalia runcinata | Kunth | Asteraceae | 4 |
| Chthamalia chihuahuensis | (A.Gray) Morillo | Apocynaceae | 4 |
| Chusquea circinata | Soderstr. & C.E.Calderón | Poaceae | 4 |
| Clematis acapulcensis | Hook. & Arn. | Ranunculaceae | 4 |
| Cnidoscolus sinaloensis | Breckon ex Fern.Casas | Euphorbiaceae | 4 |
| Cochlospermum palmatifidum | (DC.) Byng & Christenh. | Bixaceae | 4 |
| Condea decipiens | (M.E.Jones) Harley & J.F.B.Pastore | Lamiaceae | 4 |
| Cosmos linearifolius | (Sch.Bip.) Hemsl. | Asteraceae | 4 |
| Coulteria velutina | (Britton & Rose) Sotuyo & G.P.Lewis | Fabaceae | 4 |
| Crataegus rosei | Eggl. | Rosaceae | 4 |
| Ctenodon histrix | (Poir.) D.B.O.S.Cardoso, P.L.R.Moraes & H.C.Lima | Fabaceae | 4 |
| Cuscuta americana | L. | Convolvulaceae | 4 |
| Cuscuta leptantha | Engelm. | Convolvulaceae | 4 |
| Cynanchum ligulatum | (Benth.) Woodson | Apocynaceae | 4 |
| Cyperus dipsaceus | Liebm. | Cyperaceae | 4 |
| Desmodium distortum | (Aubl.) J.F.Macbr. | Fabaceae | 4 |
| Dimorphocarpa pinnatifida | Rollins | Brassicaceae | 4 |
| Diphysa occidentalis | Rose | Fabaceae | 4 |
| Diplacus aridus | Abrams | Phrymaceae | 4 |
| Drymaria arenarioides | Humb. & Bonpl. ex Schult. | Caryophyllaceae | 4 |
| Dyscritogyne dryophila | (B.L.Rob.) R.M.King & H.Rob. | Asteraceae | 4 |
| Encelia laciniata | Vasey & Rose | Asteraceae | 4 |
| Ericameria martirensis | Wiggins | Asteraceae | 4 |
| Erythranthe pallens | (Greene) G.L.Nesom | Phrymaceae | 4 |
| Eucnide rupestris | (Baill.) H.J.Thomps. & W.R.Ernst | Loasaceae | 4 |
| Euphorbia ocymoidea | L. | Euphorbiaceae | 4 |
| Ferocactus alamosanus | (Britton & Rose) Britton & Rose | Cactaceae | 4 |
| Ficus velutina | Humb. & Bonpl. ex Willd. | Moraceae | 4 |
| Gaga marginata | (Kunth) Fay W.Li & Windham | Pteridaceae | 4 |
| Garcia nutans | Rohr | Euphorbiaceae | 4 |
| Gaya minutiflora | Rose | Malvaceae | 4 |
| Gentianella canosoi | G.L.Nesom & B.L.Turner | Gentianaceae | 4 |
| Gonolobus arizonicus | (A.Gray) Woodson | Apocynaceae | 4 |
| Graptopetalum bartramii | Rose | Crassulaceae | 4 |
| Guardiola mexicana | Bonpl. | Asteraceae | 4 |
| Habenaria strictissima | Rchb.f. | Orchidaceae | 4 |
| Heteranthera rotundifolia | (Kunth) Griseb. | Pontederiaceae | 4 |
| Hieracium schultzii | Fr. | Asteraceae | 4 |
| Hoffmannseggia peninsularis | (Britton) Wiggins | Fabaceae | 4 |
| Hofmeisteria crassifolia | S.Watson | Asteraceae | 4 |
| Hofmeisteria urenifolia | Walp. | Asteraceae | 4 |
| Ilex discolor | Hemsl. | Aquifoliaceae | 4 |
| Ipomopsis pringlei | (A.Gray) Henrickson | Polemoniaceae | 4 |
| Juncus bryoides | F.J.Herm. | Juncaceae | 4 |
| Juncus covillei | Piper | Juncaceae | 4 |
| Lasianthaea ceanothifolia | (Willd.) K.M.Becker | Asteraceae | 4 |
| Lepidium dictyotum | A.Gray | Brassicaceae | 4 |
| Lippia formosa | Brandegee | Verbenaceae | 4 |
| Lucuma campechiana | Kunth | Sapotaceae | 4 |
| Lysiloma watsonii | Rose | Fabaceae | 4 |
| Lythrum gracile | Benth. | Lythraceae | 4 |
| Mammillaria peninsularis | (Britton & Rose) Orcutt | Cactaceae | 4 |
| Muhlenbergia mutica | (Rupr. ex Galeotti) Hitchc. | Poaceae | 4 |
| Muhlenbergia ramulosa | (Kunth) Swallen | Poaceae | 4 |
| Myriopteris pringlei | (Davenp.) Grusz & Windham | Pteridaceae | 4 |
| Nectandra hihua | (Ruiz & Pav.) Rohwer | Lauraceae | 4 |
| Nolina beldingii | Brandegee | Asparagaceae | 4 |
| Ouratea mexicana | (Bonpl.) Engl. | Ochnaceae | 4 |
| Packera candidissima | (Greene) W.A.Weber & Á.Löve | Asteraceae | 4 |
| Pecluma struthionis | (L.) Boudrie, Cremers & Viane | Polypodiaceae | 4 |
| Pectocarya peninsularis | I.M.Johnst. | Boraginaceae | 4 |
| Penstemon eximius | D.D.Keck | Plantaginaceae | 4 |
| Peperomia angustata | Kunth | Piperaceae | 4 |
| Persea liebmannii | Mez | Lauraceae | 4 |
| Pisonia flavescens | Standl. | Nyctaginaceae | 4 |
| Plagiobothrys leptocladus | (Greene) I.M.Johnst. | Boraginaceae | 4 |
| Potentilla subviscosa | Greene | Rosaceae | 4 |
| Prunus zinggii | Standl. | Rosaceae | 4 |
| Quercus mexicana | Bonpl. | Fagaceae | 4 |
| Randia pringlei | A.Gray | Rubiaceae | 4 |
| Rhinotropis desertorum | (Brandegee) J.R.Abbott | Polygalaceae | 4 |
| Russelia tenuis | Lundell | Plantaginaceae | 4 |
| Sairocarpus watsonii | (Vasey & Rose) D.A.Sutton | Plantaginaceae | 4 |
| Salvia aequidistans | Fernald | Lamiaceae | 4 |
| Salvia cedrosensis | Greene | Lamiaceae | 4 |
| Sceptridium schaffneri | (Underw.) Lyon | Ophioglossaceae | 4 |
| Schizachyrium condensatum | (Kunth) Nees | Poaceae | 4 |
| Sedum bourgaei | Hemsl. | Crassulaceae | 4 |
| Senna foetidissima | (Ruiz & Pav. ex G.Don) H.S.Irwin & Barneby | Fabaceae | 4 |
| Sidastrum paniculatum | (L.) Fryxell | Malvaceae | 4 |
| Sigesbeckia agrestis | Poepp. & Endl. | Asteraceae | 4 |
| Sinclairia palmeri | (A.Gray) B.L.Turner | Asteraceae | 4 |
| Sisyrinchium arizonicum | Rothr. | Iridaceae | 4 |
| Spermacoce tenuior | L. | Rubiaceae | 4 |
| Stegnosperma cubense | A.Rich. | Stegnospermataceae | 4 |
| Stenocereus montanus | (Britton & Rose) Buxb. | Cactaceae | 4 |
| Stevia aschenborniana | Sch.Bip. | Asteraceae | 4 |
| Stevia berlandieri | A.Gray | Asteraceae | 4 |
| Stevia origanoides | Kunth | Asteraceae | 4 |
| Struthanthus palmeri | Kuijt | Loranthaceae | 4 |
| Stylosanthes humilis | Kunth | Fabaceae | 4 |
| Suaeda esteroa | Ferren & S.A.Whitmore | Chenopodiaceae | 4 |
| Ternstroemia maltbya | Rose | Pentaphylacaceae | 4 |
| Thorneochloa diegoensis | (Swallen) Romasch. | Poaceae | 4 |
| Tillandsia eistetteri | Ehlers | Bromeliaceae | 4 |
| Tridax tenuifolia | Rose | Asteraceae | 4 |
| Vachellia californica | (Brandegee) Seigler & Ebinger | Fabaceae | 4 |
| Valeriana urticifolia | Kunth | Caprifoliaceae | 4 |
| Verbena delticola | Small ex Perry | Verbenaceae | 4 |
| Viguiera decurrens | (A.Gray) A.Gray | Asteraceae | 4 |
| Acalypha adenostachya | Müll.Arg. | Euphorbiaceae | 3 |
| Acalypha membranacea | A.Rich. | Euphorbiaceae | 3 |
| Achimenes glabrata | (Zucc.) Fritsch | Gesneriaceae | 3 |
| Acmispon argyraeus | (Greene) Brouillet | Fabaceae | 3 |
| Adiantum deflectens | Mart. | Pteridaceae | 3 |
| Agave sobria | Brandegee | Asparagaceae | 3 |
| Agave vizcainoensis | Gentry | Asparagaceae | 3 |
| Agave wocomahi | Gentry | Asparagaceae | 3 |
| Agrostis variabilis | Rydb. | Poaceae | 3 |
| Allobriquetia spicata | (Kunth) Bovini | Malvaceae | 3 |
| Alternanthera lanceolata | (Benth.) Schinz | Amaranthaceae | 3 |
| Amaranthus crassipes | Schltdl. | Amaranthaceae | 3 |
| Ammannia grayi | S.A.Graham & Gandhi | Lythraceae | 3 |
| Amyris balsamifera | L. | Rutaceae | 3 |
| Andropogon tener | (Nees) Kunth | Poaceae | 3 |
| Aralia scopulorum | Brandegee | Araliaceae | 3 |
| Asanthus solidaginifolius | (A.Gray) R.M.King & H.Rob. | Asteraceae | 3 |
| Asclepias elata | Benth. | Apocynaceae | 3 |
| Asclepias macrotis | Torr. | Apocynaceae | 3 |
| Asclepias subaphylla | Woodson | Apocynaceae | 3 |
| Astragalus insularis | Kellogg | Fabaceae | 3 |
| Astranthium orthopodum | Larsen | Asteraceae | 3 |
| Ayenia peninsularis | Brandegee | Malvaceae | 3 |
| Barkeria barkeriola | Rchb.f. | Orchidaceae | 3 |
| Barkeria palmeri | (Rolfe) Schltr. | Orchidaceae | 3 |
| Barroetea subuligera | A.Gray | Asteraceae | 3 |
| Bauhinia pringlei | S.Watson | Fabaceae | 3 |
| Bletia adenocarpa | Rchb.f. | Orchidaceae | 3 |
| Bletia macristhmochila | Greenm. | Orchidaceae | 3 |
| Bouteloua erecta | (Vasey & Hack.) Columbus | Poaceae | 3 |
| Bouteloua reflexa | Swallen | Poaceae | 3 |
| Bryantiella palmeri | (S.Watson) J.M.Porter | Polemoniaceae | 3 |
| Carminatia recondita | McVaugh | Asteraceae | 3 |
| Castilleja durangensis | G.L.Nesom | Orobanchaceae | 3 |
| Ceanothus ochraceus | Suess. | Rhamnaceae | 3 |
| Ceratopteris pteridoides | (Hook.) Hieron. | Pteridaceae | 3 |
| Cestrum racemosum | Ruiz & Pav. | Solanaceae | 3 |
| Chenopodium desiccatum | A.Nelson | Chenopodiaceae | 3 |
| Clematis rhodocarpa | Rose | Ranunculaceae | 3 |
| Cochemiea wrightii | (Engelm. & J.M.Bigelow) Doweld | Cactaceae | 3 |
| Coenoemersa limosa | (Lindl.) R.González & Lizb.Hern. | Orchidaceae | 3 |
| Corchorus hirtus | L. | Malvaceae | 3 |
| Coreocarpus parthenioides | Benth. | Asteraceae | 3 |
| Critonia peninsularis | (Brandegee) R.M.King & H.Rob. | Asteraceae | 3 |
| Crotalaria bupleurifolia | Schltdl. & Cham. | Fabaceae | 3 |
| Cryptantha decipiens | (M.E.Jones) A.Heller | Boraginaceae | 3 |
| Cuscuta legitima | Costea & Stefanović | Convolvulaceae | 3 |
| Cylindropuntia calmalliana | (J.M.Coult.) F.M.Knuth | Cactaceae | 3 |
| Cyperus tenerrimus | J.Presl & C.Presl | Cyperaceae | 3 |
| Dalea lumholtzii | C.B.Rob. & Fernald | Fabaceae | 3 |
| Dalembertia populifolia | Baill. | Euphorbiaceae | 3 |
| Daucus montanus | Humb. & Bonpl. ex Schult. | Apiaceae | 3 |
| Diectomis fastigiata | (Sw.) P.Beauv. | Poaceae | 3 |
| Distichlis bajaensis | H.L.Bell | Poaceae | 3 |
| Distichlis palmeri | (Vasey) Fassett ex I.M.Johnst. | Poaceae | 3 |
| Dudleya brittonii | Johans. | Crassulaceae | 3 |
| Dudleya gatesii | D.A.Johans. | Crassulaceae | 3 |
| Echeandia gentryi | Cruden | Asparagaceae | 3 |
| Elaphoglossum sartorii | (Liebm.) Mickel | Dryopteridaceae | 3 |
| Erigeron lobatus | A.Nelson | Asteraceae | 3 |
| Erigeron versicolor | (Greenm.) G.L.Nesom | Asteraceae | 3 |
| Erythranthe flammea | G.L.Nesom | Phrymaceae | 3 |
| Erythranthe latidens | (A.Gray) G.L.Nesom | Phrymaceae | 3 |
| Eucnide aurea | (A.Gray) H.J.Thomps. & W.R.Ernst | Loasaceae | 3 |
| Eulobus angelorum | (S.Watson) W.L.Wagner & Hoch | Onagraceae | 3 |
| Euphorbia alta | Norton | Euphorbiaceae | 3 |
| Euphorbia lancifolia | Schltdl. | Euphorbiaceae | 3 |
| Euphorbia pumicicola | Huft | Euphorbiaceae | 3 |
| Euphorbia sphaerorhiza | Benth. | Euphorbiaceae | 3 |
| Euploca humilis | (L.) Feuillet | Heliotropiaceae | 3 |
| Forestiera durangensis | Standl. | Oleaceae | 3 |
| Frankenia gypsophila | I.M.Johnst. | Frankeniaceae | 3 |
| Fraxinus gooddingii | Little | Oleaceae | 3 |
| Galium uncinulatum | DC. | Rubiaceae | 3 |
| Galphimia tuberculata | (Rose) Nied. | Malpighiaceae | 3 |
| Gentianella amarella | (L.) Börner | Gentianaceae | 3 |
| Gentianopsis lanceolata | (Benth.) Iltis | Gentianaceae | 3 |
| Geranium niveum | S.Watson | Geraniaceae | 3 |
| Gibasis venustula | (Kunth) D.R.Hunt | Commelinaceae | 3 |
| Gongylocarpus rubricaulis | Cham. & Schltdl. | Onagraceae | 3 |
| Grusonia reflexispina | (Wiggins & Rollins) E.F.Anderson | Cactaceae | 3 |
| Halenia recurva | (Sm.) C.K.Allen | Gentianaceae | 3 |
| Harpagonella arizonica | (I.M.Johnst.) Guilliams & B.G.Baldwin | Boraginaceae | 3 |
| Heliocarpus appendiculatus | Turcz. | Malvaceae | 3 |
| Heteropterys cotinifolia | A.Juss. | Malpighiaceae | 3 |
| Horsfordia rotundifolia | S.Watson | Malvaceae | 3 |
| Hydrangea seemannii | L.Riley | Hydrangeaceae | 3 |
| Hymenostephium tenue | (A.Gray) E.E.Schill. & Panero | Asteraceae | 3 |
| Ipomoea tenuiloba | Torr. | Convolvulaceae | 3 |
| Ipomopsis effusa | (A.Gray) Moran | Polemoniaceae | 3 |
| Ipomopsis guttata | (A.Gray) Moran | Polemoniaceae | 3 |
| Iresine schaffneri | S.Watson | Amaranthaceae | 3 |
| Juncus textilis | Buchenau | Juncaceae | 3 |
| Koanophyllon palmeri | (A.Gray) R.M.King & H.Rob. | Asteraceae | 3 |
| Krameria paucifolia | Rose | Krameriaceae | 3 |
| Leptosiphon laxus | (Vasey & Rose) J.M.Porter & L.A.Johnson | Polemoniaceae | 3 |
| Leucaena macrophylla | Benth. | Fabaceae | 3 |
| Leucosyris coulteri | (A.Gray) Pruski & R.L.Hartm. | Asteraceae | 3 |
| Leucosyris parviflora | (A.Gray) Pruski & R.L.Hartm. | Asteraceae | 3 |
| Lobelia sinaloae | Sprague | Campanulaceae | 3 |
| Lonchocarpus punctatus | Kunth | Fabaceae | 3 |
| Lopezia clavata | Brandegee | Onagraceae | 3 |
| Lopezia semeiandra | Plitmann, P.H.Raven & Breedlove | Onagraceae | 3 |
| Mandevilla brachysiphon | (Torr.) Pichon | Apocynaceae | 3 |
| Marina brevis | León de la Luz | Fabaceae | 3 |
| Marina peninsularis | (Rose) Barneby | Fabaceae | 3 |
| Mariosousa heterophylla | (Benth.) Seigler & Ebinger | Fabaceae | 3 |
| Mentzelia isolata | Gentry | Loasaceae | 3 |
| Mesosphaerum collinum | (Brandegee) Harley & J.F.B.Pastore | Lamiaceae | 3 |
| Miconia madrensis | Standl. | Melastomataceae | 3 |
| Mitracarpus breviflorus | A.Gray | Rubiaceae | 3 |
| Muhlenbergia appressa | Goodd. | Poaceae | 3 |
| Muhlenbergia pauciflora | Buckley | Poaceae | 3 |
| Muhlenbergia repens | (J.Presl) Hitchc. | Poaceae | 3 |
| Nama undulata | Kunth | Namaceae | 3 |
| Nephrolepis undulata | (Afzel. ex Sw.) J.Sm. | Nephrolepidaceae | 3 |
| Oenothera havardii | S.Watson | Onagraceae | 3 |
| Ophioglossum reticulatum | L. | Ophioglossaceae | 3 |
| Opuntia clarkiorum | Rebman | Cactaceae | 3 |
| Orthosia mexicana | (S.Watson) Liede & Meve | Apocynaceae | 3 |
| Oxypappus scaber | Benth. | Asteraceae | 3 |
| Panicum urvilleanum | Kunth | Poaceae | 3 |
| Pectis imberbis | A.Gray | Asteraceae | 3 |
| Pectis longipes | A.Gray | Asteraceae | 3 |
| Peltostigma pteleoides | (Hook.) Walp. | Rutaceae | 3 |
| Phanerophlebia auriculata | Underw. | Dryopteridaceae | 3 |
| Phaseolus ritensis | M.E.Jones | Fabaceae | 3 |
| Phemeranthus parvulus | (Rose & Standl.) D.J.Ferguson & T.M.Price | Montiaceae | 3 |
| Phyllanthus acuminatus | Vahl | Phyllanthaceae | 3 |
| Pitcairnia palmeri | S.Watson | Bromeliaceae | 3 |
| Polystemma fuscum | (Decne.) C.Cerv., S.Arias & L.O.Alvarado | Apocynaceae | 3 |
| Porophyllum pausodynum | B.L.Rob. & Greenm. | Asteraceae | 3 |
| Prosthechea squalida | (Lex.) Soto Arenas & Salazar | Orchidaceae | 3 |
| Psacalium megaphyllum | Rydb. | Asteraceae | 3 |
| Psacalium radulifolium | (Kunth) H.Rob. & Brettell | Asteraceae | 3 |
| Pseudabutilon scabrum | (C.Presl) R.E.Fr. | Malvaceae | 3 |
| Pseudoeriocoma eminens | (Cav.) Romasch. | Poaceae | 3 |
| Pteridium latiusculum | Hieron. | Dennstaedtiaceae | 3 |
| Quercus ajoensis | C.H.Mull. | Fagaceae | 3 |
| Quercus tarahumara | Spellenb., J.R.Bacon & Breedlove | Fagaceae | 3 |
| Ranunculus cupulatus | (S.Watson) Christenh. & Byng | Ranunculaceae | 3 |
| Rhipidocladum racemiflorum | (Steud.) McClure | Poaceae | 3 |
| Rhus tepetate | Standl. & F.A.Barkley | Anacardiaceae | 3 |
| Ricoa leptophylla | (DC.) Duno & Torke | Fabaceae | 3 |
| Ruehssia coulteri | (Hemsl.) L.O.Alvarado | Apocynaceae | 3 |
| Rupertia rigida | (Parish) J.W.Grimes | Fabaceae | 3 |
| Salpianthus macrodontus | Standl. | Nyctaginaceae | 3 |
| Sambucus mexicana | C.Presl ex DC. | Viburnaceae | 3 |
| Selaginella asprella | Maxon | Selaginellaceae | 3 |
| Senecio stoechadiformis | DC. | Asteraceae | 3 |
| Sidastrum lodiegense | (Baker) Fryxell | Malvaceae | 3 |
| Sideroxylon palmeri | (Rose) T.D.Penn. | Sapotaceae | 3 |
| Sideroxylon peninsulare | (Brandegee) T.D.Penn. | Sapotaceae | 3 |
| Solanum stenophyllidium | Bitter | Solanaceae | 3 |
| Stellaria ovata | Willd. ex D.F.K.Schltdl. | Caryophyllaceae | 3 |
| Stephanomeria paniculata | Nutt. | Asteraceae | 3 |
| Styrax radians | P.W.Fritsch | Styracaceae | 3 |
| Tagetes lacera | Brandegee | Asteraceae | 3 |
| Tamayorkis porphyrea | (Ridl.) Salazar & Soto Arenas | Orchidaceae | 3 |
| Tessiera lithospermoides | DC. | Rubiaceae | 3 |
| Tiquilia mexicana | (S.Watson) A.T.Richardson | Ehretiaceae | 3 |
| Vauquelinia californica | (Torr.) Sarg. | Rosaceae | 3 |
| Viola umbraticola | Kunth | Violaceae | 3 |
| Vitis peninsularis | M.E.Jones | Vitaceae | 3 |
| Waltheria conzattii | Standl. | Malvaceae | 3 |
| Wedelia greenmanii | B.L.Turner | Asteraceae | 3 |
| Woodsia cochisensis | Windham | Woodsiaceae | 3 |
| Xylonagra arborea | (Kellogg) Donn.Sm. & Rose | Onagraceae | 3 |
| Zanthoxylum caribaeum | Lam. | Rutaceae | 3 |