| Abdra brachycarpa | Greene | Brassicaceae | 8 |
| Abies concolor | (Gordon) Lindl. ex Hildebr. | Pinaceae | 8 |
| Abies lasiocarpa | (Hook.) Nutt. | Pinaceae | 8 |
| Abronia angustifolia | Greene | Nyctaginaceae | 8 |
| Abronia carnea | Greene | Nyctaginaceae | 8 |
| Abronia elliptica | A.Nelson | Nyctaginaceae | 8 |
| Abronia fragrans | Nutt. ex Hook. | Nyctaginaceae | 8 |
| Abronia nana | S.Watson | 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 |
| Acaciella angustissima | (Mill.) Britton & Rose | Fabaceae | 8 |
| Acalypha californica | Benth. | Euphorbiaceae | 8 |
| Acalypha mexicana | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha neomexicana | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha persimilis | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha phleoides | Cav. | Euphorbiaceae | 8 |
| Acamptopappus sphaerocephalus | A.Gray | Asteraceae | 8 |
| Acer glabrum | Torr. | Sapindaceae | 8 |
| Acer negundo | L. | Sapindaceae | 8 |
| Acer saccharum | Marshall | Sapindaceae | 8 |
| Achillea millefolium | L. | Asteraceae | 8 |
| Achyronychia cooperi | A.Gray | Caryophyllaceae | 8 |
| Acleisanthes chenopodioides | (A.Gray) R.A.Levin | Nyctaginaceae | 8 |
| Acleisanthes longiflora | A.Gray | Nyctaginaceae | 8 |
| Acleisanthes nevadensis | (Standl.) B.L.Turner | Nyctaginaceae | 8 |
| Acmispon americanus | (Nutt.) Rydb. | Fabaceae | 8 |
| Acmispon brachycarpus | (Benth.) D.D.Sokoloff | Fabaceae | 8 |
| Acmispon glaber | (Vogel) Brouillet | Fabaceae | 8 |
| Acmispon maritimus | (Nutt.) D.D.Sokoloff | Fabaceae | 8 |
| Acmispon mearnsii | (Britton) Brouillet | Fabaceae | 8 |
| Acmispon micranthus | (Nutt. ex Torr. & A.Gray) Brouillet | Fabaceae | 8 |
| Acmispon neomexicanus | (Greene) Brouillet | Fabaceae | 8 |
| Acmispon oroboides | (Kunth) Brouillet | Fabaceae | 8 |
| Acmispon rigidus | (Benth.) Brouillet | Fabaceae | 8 |
| Acmispon utahensis | (Ottley) Brouillet | Fabaceae | 8 |
| Acmispon wrightii | (A.Gray) Brouillet | Fabaceae | 8 |
| Aconitum columbianum | Nutt. | Ranunculaceae | 8 |
| Acourtia nana | (A.Gray) Reveal & R.M.King | Asteraceae | 8 |
| Acourtia wrightii | (A.Gray) Reveal & R.M.King | Asteraceae | 8 |
| Actaea rubra | (Aiton) Willd. | Ranunculaceae | 8 |
| Adenophyllum cooperi | (A.Gray) Strother | Asteraceae | 8 |
| Adenophyllum porophylloides | (A.Gray) Strother | Asteraceae | 8 |
| Adenophyllum wrightii | A.Gray | Asteraceae | 8 |
| Adiantum aleuticum | (Rupr.) C.A.Paris | Pteridaceae | 8 |
| Adiantum capillus-veneris | L. | Pteridaceae | 8 |
| Adolphia infesta | (Kunth) Meisn. | Rhamnaceae | 8 |
| Aeschynomene villosa | Poir. | Fabaceae | 8 |
| Agastache pallida | (Lindl.) Cory | Lamiaceae | 8 |
| Agastache pallidiflora | (A.Heller) Rydb. | Lamiaceae | 8 |
| Agave americana | L. | Asparagaceae | 8 |
| Agave chrysantha | Peebles | Asparagaceae | 8 |
| Agave mckelveyana | Gentry | Asparagaceae | 8 |
| Agave palmeri | Engelm. | Asparagaceae | 8 |
| Agave parryi | Engelm. | Asparagaceae | 8 |
| Agave schottii | Engelm. | Asparagaceae | 8 |
| Agave utahensis | Engelm. | Asparagaceae | 8 |
| Ageratina herbacea | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina paupercula | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina rothrockii | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratina wrightii | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Ageratum corymbosum | Zucc. ex Pers. | Asteraceae | 8 |
| Agoseris aurantiaca | (Hook.) Greene | Asteraceae | 8 |
| Agoseris glauca | (Pursh) Raf. | Asteraceae | 8 |
| Agoseris heterophylla | (Nutt.) Greene | Asteraceae | 8 |
| Agoseris retrorsa | Greene | Asteraceae | 8 |
| Agrimonia gryposepala | Wallr. | Rosaceae | 8 |
| Agrimonia striata | Michx. | Rosaceae | 8 |
| Agrostis scabra | Willd. | Poaceae | 8 |
| Aldama cordifolia | (A.Gray) E.E.Schill. & Panero | Asteraceae | 8 |
| Aliciella hutchinsifolia | (Rydb.) J.M.Porter | Polemoniaceae | 8 |
| Aliciella latifolia | (S.Watson) J.M.Porter | Polemoniaceae | 8 |
| Aliciella leptomeria | (A.Gray) J.M.Porter | Polemoniaceae | 8 |
| Aliciella lottiae | (A.G.Day) J.M.Porter | Polemoniaceae | 8 |
| Aliciella subnuda | (Torr. ex A.Gray) J.M.Porter | Polemoniaceae | 8 |
| Aliciella triodon | (Eastw.) Brand | Polemoniaceae | 8 |
| Alisma gramineum | Lej. | Alismataceae | 8 |
| Alisma triviale | Pursh | Alismataceae | 8 |
| Allenrolfea occidentalis | (S.Watson) Kuntze | Chenopodiaceae | 8 |
| Allionia choisyi | Standl. | Nyctaginaceae | 8 |
| Allionia incarnata | L. | Nyctaginaceae | 8 |
| Allium acuminatum | Hook. | Amaryllidaceae | 8 |
| Allium bisceptrum | S.Watson | Amaryllidaceae | 8 |
| Allium cernuum | Roth | Amaryllidaceae | 8 |
| Allium geyeri | S.Watson | Amaryllidaceae | 8 |
| Allium longifolium | (Kunth) Spreng. | Amaryllidaceae | 8 |
| Allium macropetalum | Rydb. | Amaryllidaceae | 8 |
| Allium nevadense | S.Watson | Amaryllidaceae | 8 |
| Allium rhizomatum | Wooton & Standl. | Amaryllidaceae | 8 |
| Allophyllum gilioides | (Benth.) A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Alnus incana | (L.) Moench | Betulaceae | 8 |
| Alnus oblongifolia | Torr. | Betulaceae | 8 |
| Alopecurus aequalis | Sobol. | Poaceae | 8 |
| Alopecurus carolinianus | Walter | Poaceae | 8 |
| Aloysia gratissima | (Gillies & Hook.) Tronc. | Verbenaceae | 8 |
| Aloysia wrightii | A.Heller | Verbenaceae | 8 |
| Amaranthus albus | L. | Amaranthaceae | 8 |
| Amaranthus fimbriatus | (Torr.) Benth. ex S.Watson | Amaranthaceae | 8 |
| Amaranthus palmeri | S.Watson | Amaranthaceae | 8 |
| Amaranthus powellii | S.Watson | Amaranthaceae | 8 |
| Amaranthus watsonii | Standl. | Amaranthaceae | 8 |
| Ambrosia acanthicarpa | Hook. | Asteraceae | 8 |
| Ambrosia ambrosioides | (Delpino) W.W.Payne | Asteraceae | 8 |
| Ambrosia artemisiifolia | L. | 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 eriocentra | (A.Gray) W.W.Payne | Asteraceae | 8 |
| Ambrosia ilicifolia | (A.Gray) W.W.Payne | Asteraceae | 8 |
| Ambrosia psilostachya | DC. | Asteraceae | 8 |
| Ambrosia trifida | L. | Asteraceae | 8 |
| Amelanchier alnifolia | (Nutt.) Nutt. ex M.Roem. | Rosaceae | 8 |
| Amelanchier utahensis | Koehne | Rosaceae | 8 |
| Ammannia auriculata | Willd. | Lythraceae | 8 |
| Ammannia coccinea | Rottb. | Lythraceae | 8 |
| Ammannia robusta | Heer & Regel | Lythraceae | 8 |
| Amorpha californica | Nutt. | Fabaceae | 8 |
| Amorpha canescens | Pursh | Fabaceae | 8 |
| Amorpha fruticosa | L. | Fabaceae | 8 |
| Amphipappus fremontii | Torr. & A.Gray | Asteraceae | 8 |
| Amsinckia menziesii | (Lehm.) A.Nelson & J.F.Macbr. | Boraginaceae | 8 |
| Amsinckia tessellata | A.Gray | Boraginaceae | 8 |
| Amsonia palmeri | A.Gray | Apocynaceae | 8 |
| Amsonia tomentosa | Torr. & Frém. | Apocynaceae | 8 |
| Anaphalis margaritacea | (L.) Benth. & Hook.f. | Asteraceae | 8 |
| Andropogon cirratus | Hack. | Poaceae | 8 |
| Andropogon hallii | Hack. | Poaceae | 8 |
| Androsace occidentalis | Pursh | Primulaceae | 8 |
| Androsace septentrionalis | L. | Primulaceae | 8 |
| Androstephium breviflorum | S.Watson | Asparagaceae | 8 |
| Anemone cylindrica | A.Gray | Ranunculaceae | 8 |
| Anemone multifida | Poir. | Ranunculaceae | 8 |
| Anemone tuberosa | Rydb. | Ranunculaceae | 8 |
| Anemopsis californica | (Nutt.) Hook. & Arn. | Saururaceae | 8 |
| Angelica pinnata | S.Watson | Apiaceae | 8 |
| Anisacanthus thurberi | (Torr.) A.Gray | Acanthaceae | 8 |
| Anisocoma acaulis | Torr. & A.Gray | Asteraceae | 8 |
| Anoda crenatiflora | Ortega | Malvaceae | 8 |
| Anoda cristata | (L.) Schltdl. | Malvaceae | 8 |
| Anoda lanceolata | Hook. & Arn. | Malvaceae | 8 |
| Anoda pentaschista | A.Gray | Malvaceae | 8 |
| Antennaria marginata | Greene | Asteraceae | 8 |
| Antennaria media | Greene | Asteraceae | 8 |
| Antennaria microphylla | Rydb. | Asteraceae | 8 |
| Antennaria parvifolia | Nutt. | Asteraceae | 8 |
| Antennaria rosea | Greene | Asteraceae | 8 |
| Antennaria rosulata | Rydb. | Asteraceae | 8 |
| Antennaria umbrinella | Rydb. | Asteraceae | 8 |
| Anthoxanthum nitens | (Weber) Y.Schouten & Veldkamp | Poaceae | 8 |
| Anticlea elegans | (Pursh) Rydb. | Melanthiaceae | 8 |
| Anticlea virescens | (Kunth) Rydb. | Melanthiaceae | 8 |
| Aphanostephus ramosissimus | DC. | Asteraceae | 8 |
| Apocynum androsaemifolium | L. | Apocynaceae | 8 |
| Apocynum cannabinum | L. | Apocynaceae | 8 |
| Apodanthera undulata | A.Gray | Cucurbitaceae | 8 |
| Aquilegia chrysantha | A.Gray | Ranunculaceae | 8 |
| Aquilegia coerulea | E.James | Ranunculaceae | 8 |
| Aquilegia desertorum | (M.E.Jones) Cockerell ex A.Heller | Ranunculaceae | 8 |
| Aquilegia elegantula | Greene | Ranunculaceae | 8 |
| Aquilegia longissima | A.Gray ex S.Watson | Ranunculaceae | 8 |
| Aquilegia micrantha | Eastw. | Ranunculaceae | 8 |
| Aralia bicrenata | Wooton & Standl. | Araliaceae | 8 |
| Aralia humilis | Cav. | Araliaceae | 8 |
| Arbutus arizonica | (A.Gray) Sarg. | Ericaceae | 8 |
| Arceuthobium divaricatum | Engelm. | Santalaceae | 8 |
| Arceuthobium douglasii | Engelm. | Santalaceae | 8 |
| Arceuthobium vaginatum | (Humb. & Bonpl. ex Willd.) J.Presl | Santalaceae | 8 |
| Arctostaphylos patula | Greene | Ericaceae | 8 |
| Arctostaphylos pringlei | Parry | Ericaceae | 8 |
| Arctostaphylos pungens | Kunth | Ericaceae | 8 |
| Arctostaphylos uva-ursi | (L.) Spreng. | Ericaceae | 8 |
| Arenaria lanuginosa | (Michx.) Rohrb. | Caryophyllaceae | 8 |
| Argemone corymbosa | Greene | Papaveraceae | 8 |
| Argemone munita | Durand & Hilg. | 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 |
| Aristida adscensionis | L. | Poaceae | 8 |
| Aristida arizonica | Vasey | Poaceae | 8 |
| Aristida divaricata | Humb. & Bonpl. ex Willd. | Poaceae | 8 |
| Aristida longespica | Poir. | Poaceae | 8 |
| Aristida oligantha | Michx. | Poaceae | 8 |
| Aristida pansa | Wooton & Standl. | Poaceae | 8 |
| Aristida purpurea | Nutt. | Poaceae | 8 |
| Aristida ternipes | Cav. | Poaceae | 8 |
| Aristolochia watsonii | Wooton & Standl. | Aristolochiaceae | 8 |
| Arnica chamissonis | Less. | Asteraceae | 8 |
| Arnica cordifolia | Hook. | Asteraceae | 8 |
| Artemisia biennis | Willd. | Asteraceae | 8 |
| Artemisia bigelovii | A.Gray | Asteraceae | 8 |
| Artemisia campestris | L. | Asteraceae | 8 |
| Artemisia cana | Pursh | Asteraceae | 8 |
| Artemisia carruthii | Alph.Wood ex J.H.Carruth | Asteraceae | 8 |
| Artemisia dracunculus | L. | Asteraceae | 8 |
| Artemisia filifolia | Torr. | Asteraceae | 8 |
| Artemisia frigida | Willd. | Asteraceae | 8 |
| Artemisia ludoviciana | Nutt. | Asteraceae | 8 |
| Artemisia nova | A.Nelson | Asteraceae | 8 |
| Artemisia pygmaea | 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 cryptoceras | S.Watson | Apocynaceae | 8 |
| Asclepias erosa | Torr. | Apocynaceae | 8 |
| Asclepias hallii | A.Gray | Apocynaceae | 8 |
| Asclepias hypoleuca | (A.Gray) Woodson | Apocynaceae | 8 |
| Asclepias incarnata | L. | Apocynaceae | 8 |
| Asclepias involucrata | Engelm. ex Torr. | Apocynaceae | 8 |
| Asclepias latifolia | (Torr.) Raf. | 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 rusbyi | (Vail) Woodson | Apocynaceae | 8 |
| Asclepias speciosa | Torr. | Apocynaceae | 8 |
| Asclepias subulata | Decne. | Apocynaceae | 8 |
| Asclepias subverticillata | (A.Gray) Vail | Apocynaceae | 8 |
| Asclepias tuberosa | L. | Apocynaceae | 8 |
| Asclepias verticillata | L. | Apocynaceae | 8 |
| Asclepias viridiflora | Raf. | Apocynaceae | 8 |
| Asclepias welshii | N.H.Holmgren & P.K.Holmgren | Apocynaceae | 8 |
| Aspicarpa hirtella | Rich. | Malpighiaceae | 8 |
| Asplenium adiantum-nigrum | L. | Aspleniaceae | 8 |
| Asplenium monanthes | L. | Aspleniaceae | 8 |
| Asplenium platyneuron | (L.) Britton, Sterns & Poggenb. | Aspleniaceae | 8 |
| Asplenium resiliens | Kunze | Aspleniaceae | 8 |
| Asplenium septentrionale | (L.) Hoffm. | Aspleniaceae | 8 |
| Asplenium trichomanes | L. | Aspleniaceae | 8 |
| Astragalus acutirostris | S.Watson | Fabaceae | 8 |
| Astragalus allochrous | A.Gray | Fabaceae | 8 |
| Astragalus amphioxys | A.Gray | Fabaceae | 8 |
| Astragalus aridus | A.Gray | Fabaceae | 8 |
| Astragalus bisulcatus | (Hook.) A.Gray | Fabaceae | 8 |
| Astragalus brandegeei | Porter | Fabaceae | 8 |
| Astragalus calycosus | Torr. ex S.Watson | Fabaceae | 8 |
| Astragalus ceramicus | E.Sheld. | Fabaceae | 8 |
| Astragalus cobrensis | A.Gray | Fabaceae | 8 |
| Astragalus coccineus | (Parry) Brandegee | Fabaceae | 8 |
| Astragalus crassicarpus | Nutt. | Fabaceae | 8 |
| Astragalus crotalariae | (Benth.) A.Gray | Fabaceae | 8 |
| Astragalus desperatus | M.E.Jones | Fabaceae | 8 |
| Astragalus didymocarpus | Hook. & Arn. | Fabaceae | 8 |
| Astragalus emoryanus | (Rydb.) Cory | Fabaceae | 8 |
| Astragalus eremiticus | E.Sheld. | Fabaceae | 8 |
| Astragalus flavus | Nutt. | Fabaceae | 8 |
| Astragalus flexuosus | (Hook.) Douglas ex G.Don | Fabaceae | 8 |
| Astragalus gilensis | Greene | Fabaceae | 8 |
| Astragalus hallii | A.Gray | Fabaceae | 8 |
| Astragalus humistratus | A.Gray | Fabaceae | 8 |
| Astragalus kentrophyta | A.Gray | Fabaceae | 8 |
| Astragalus layneae | Greene | Fabaceae | 8 |
| Astragalus lentiginosus | Douglas ex Hook. | Fabaceae | 8 |
| Astragalus lonchocarpus | Torr. | Fabaceae | 8 |
| Astragalus miser | Douglas ex Hook. | Fabaceae | 8 |
| Astragalus missouriensis | Nutt. | Fabaceae | 8 |
| Astragalus mollissimus | Torr. | Fabaceae | 8 |
| Astragalus newberryi | A.Gray | Fabaceae | 8 |
| Astragalus nothoxys | A.Gray | Fabaceae | 8 |
| Astragalus nuttallianus | DC. | Fabaceae | 8 |
| Astragalus oophorus | S.Watson | Fabaceae | 8 |
| Astragalus palmeri | A.Gray | Fabaceae | 8 |
| Astragalus praelongus | E.Sheld. | Fabaceae | 8 |
| Astragalus preussii | A.Gray | Fabaceae | 8 |
| Astragalus sabulonum | A.Gray | Fabaceae | 8 |
| Astragalus scopulorum | Porter | Fabaceae | 8 |
| Astragalus tephrodes | A.Gray | Fabaceae | 8 |
| Astragalus thurberi | A.Gray | Fabaceae | 8 |
| Astragalus wootonii | E.Sheld. | Fabaceae | 8 |
| Astragalus zionis | M.E.Jones | 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 argentea | Nutt. | Chenopodiaceae | 8 |
| Atriplex canescens | (Pursh) Nutt. | Chenopodiaceae | 8 |
| Atriplex confertifolia | (Torr. & Frém.) S.Watson | Chenopodiaceae | 8 |
| Atriplex elegans | (Moq.) D.Dietr. | Chenopodiaceae | 8 |
| Atriplex hymenelytra | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex lentiformis | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex obovata | Moq. | Chenopodiaceae | 8 |
| Atriplex polycarpa | (Torr.) S.Watson | Chenopodiaceae | 8 |
| Atriplex saccaria | S.Watson | Chenopodiaceae | 8 |
| Ayenia compacta | Rose | Malvaceae | 8 |
| Ayenia filiformis | S.Watson | Malvaceae | 8 |
| Ayenia microphylla | A.Gray | Malvaceae | 8 |
| Azolla filiculoides | Lam. | Salviniaceae | 8 |
| Baccharis brachyphylla | A.Gray | 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 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 |
| Bebbia juncea | Greene | Asteraceae | 8 |
| Beckmannia syzigachne | (Steud.) Fernald | Poaceae | 8 |
| Berberis fremontii | Torr. | Berberidaceae | 8 |
| Berberis haematocarpa | Wooton | Berberidaceae | 8 |
| Berberis repens | Lindl. | Berberidaceae | 8 |
| Berberis trifoliolata | Moric. | Berberidaceae | 8 |
| Berberis wilcoxii | Kearney | Berberidaceae | 8 |
| Berlandiera lyrata | Benth. | Asteraceae | 8 |
| Bernardia incana | C.V.Morton | Euphorbiaceae | 8 |
| Berula erecta | (Huds.) Coville | Apiaceae | 8 |
| Betula occidentalis | Hook. | Betulaceae | 8 |
| Bidens alba | DC. | Asteraceae | 8 |
| Bidens aurea | (Aiton) Sherff | Asteraceae | 8 |
| Bidens bigelovii | A.Gray | Asteraceae | 8 |
| Bidens bipinnata | L. | Asteraceae | 8 |
| Bidens cernua | L. | Asteraceae | 8 |
| Bidens frondosa | L. | Asteraceae | 8 |
| Bidens laevis | (L.) Britton, Sterns & Poggenb. | Asteraceae | 8 |
| Bidens leptocephala | Sherff | Asteraceae | 8 |
| Bidens tenuisecta | A.Gray | Asteraceae | 8 |
| Bletia arizonica | (S.Watson) Sosa & M.W.Chase | Orchidaceae | 8 |
| Bletia spicata | (Walter) Sosa & M.W.Chase | Orchidaceae | 8 |
| Bletia warnockii | (Ames & Correll) Sosa & M.W.Chase | Orchidaceae | 8 |
| Blitum capitatum | L. | Chenopodiaceae | 8 |
| Blitum nuttallianum | Schult. | Chenopodiaceae | 8 |
| Boechera angustifolia | (Nutt.) Dorn | Brassicaceae | 8 |
| Boechera formosa | (Greene) Windham & Al-Shehbaz | Brassicaceae | 8 |
| Boechera pendulina | (Greene) W.A.Weber | Brassicaceae | 8 |
| Boechera perennans | (S.Watson) W.A.Weber | Brassicaceae | 8 |
| Boehmeria cylindrica | (L.) Sw. | Urticaceae | 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 purpurascens | A.Gray | Nyctaginaceae | 8 |
| Boerhavia scandens | L. | Nyctaginaceae | 8 |
| Boerhavia triquetra | S.Watson | Nyctaginaceae | 8 |
| Boerhavia wrightii | A.Gray | Nyctaginaceae | 8 |
| Bolboschoenus fluviatilis | (Torr.) Soják | Cyperaceae | 8 |
| Bolboschoenus maritimus | (L.) Palla | Cyperaceae | 8 |
| Bommeria hispida | Underw. | Pteridaceae | 8 |
| Bothriochloa barbinodis | (Lag.) Herter | Poaceae | 8 |
| Bothriochloa torreyana | (Steud.) Scrivanti & Anton | Poaceae | 8 |
| Botrychium crenulatum | W.H.Wagner | Ophioglossaceae | 8 |
| Botrychium lanceolatum | (Gmel.) Ångstr. | Ophioglossaceae | 8 |
| Botrychium minganense | Vict. | Ophioglossaceae | 8 |
| Botrychium pinnatum | H.St.John | Ophioglossaceae | 8 |
| Botrypus virginianus | (L.) Michx. | Ophioglossaceae | 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 dactyloides | (Nutt.) Columbus | 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 repens | (Kunth) Scribn. & Merr. | Poaceae | 8 |
| Bouteloua trifida | Thurb. ex S.Watson | Poaceae | 8 |
| Bouvardia ternifolia | (Cav.) Schltdl. | Rubiaceae | 8 |
| Bowlesia incana | Ruiz & Pav. | Apiaceae | 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 grandiflora | Nutt. | Asteraceae | 8 |
| Brickellia incana | A.Gray | Asteraceae | 8 |
| Brickellia leptophylla | (Scheele) Shinn. | Asteraceae | 8 |
| Brickellia longifolia | S.Watson | Asteraceae | 8 |
| Brickellia microphylla | (Nutt.) A.Gray | Asteraceae | 8 |
| Brickellia oblongifolia | Nutt. | Asteraceae | 8 |
| Brickellia rusbyi | A.Gray | Asteraceae | 8 |
| Brickelliastrum fendleri | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Bromus ciliatus | L. | Poaceae | 8 |
| Bromus porteri | (Coult.) Nash | Poaceae | 8 |
| Buddleja scordioides | Kunth | Scrophulariaceae | 8 |
| Buddleja sessiliflora | Kunth | Scrophulariaceae | 8 |
| Buddleja utahensis | Coville | Scrophulariaceae | 8 |
| Bulbostylis capillaris | (L.) Kunth ex C.B.Clarke | Cyperaceae | 8 |
| Bursera fagaroides | (Kunth) Engl. | Burseraceae | 8 |
| Bursera microphylla | A.Gray | Burseraceae | 8 |
| Calamagrostis canadensis | (Michx.) P.Beauv. | Poaceae | 8 |
| Calamagrostis inexpansa | A.Gray | Poaceae | 8 |
| Calamagrostis stricta | (Timm) Koeler | Poaceae | 8 |
| Calandrinia ciliata | (Ruiz & Pav.) DC. | Montiaceae | 8 |
| California macrophylla | (Hook. & Arn.) Aldasoro, C.Navarro, P.Vargas, L.Sáez & Aedo | Geraniaceae | 8 |
| Callaeum macropterum | (DC.) D.M.Johnson | Malpighiaceae | 8 |
| Calliandra eriophylla | Benth. | Fabaceae | 8 |
| Calliandra humilis | Benth. | Fabaceae | 8 |
| Callitriche heterophylla | Pursh | Plantaginaceae | 8 |
| Callitriche palustris | L. | Plantaginaceae | 8 |
| Calochortus ambiguus | (M.E.Jones) Ownbey | Liliaceae | 8 |
| Calochortus aureus | S.Watson | Liliaceae | 8 |
| Calochortus flexuosus | S.Watson | Liliaceae | 8 |
| Calochortus gunnisonii | S.Watson | Liliaceae | 8 |
| Calochortus kennedyi | Porter | Liliaceae | 8 |
| Calochortus nuttallii | Torr. | Liliaceae | 8 |
| Caltha chionophila | Greene | Ranunculaceae | 8 |
| Caltha leptosepala | DC. | Ranunculaceae | 8 |
| Calycoseris parryi | A.Gray | Asteraceae | 8 |
| Calycoseris wrightii | A.Gray | Asteraceae | 8 |
| Calypso bulbosa | (L.) Oakes | Orchidaceae | 8 |
| Calystegia longipes | (S.Watson) Brummitt | Convolvulaceae | 8 |
| Calystegia sepium | (L.) R.Br. | Convolvulaceae | 8 |
| Camissonia parvula | (Nutt. ex Torr. & A.Gray) P.H.Raven | Onagraceae | 8 |
| Camissoniopsis pallida | (Abrams) W.L.Wagner & Hoch | Onagraceae | 8 |
| Campanula parryi | A.Gray | Campanulaceae | 8 |
| Campanula petiolata | A.DC. | Campanulaceae | 8 |
| Canotia holacantha | Torr. | Celastraceae | 8 |
| Capsicum annuum | L. | Solanaceae | 8 |
| Cardamine cordifolia | A.Gray | Brassicaceae | 8 |
| Carex aquatilis | Wahlenb. | Cyperaceae | 8 |
| Carex atherodes | Spreng. | Cyperaceae | 8 |
| Carex athrostachya | Olney | Cyperaceae | 8 |
| Carex aurea | Nutt. | Cyperaceae | 8 |
| Carex bebbii | (L.H.Bailey) Olney ex Fernald | Cyperaceae | 8 |
| Carex bella | L.H.Bailey | Cyperaceae | 8 |
| Carex bonplandii | Kunth | Cyperaceae | 8 |
| Carex brevior | (Dewey) Mack. ex Lunell | Cyperaceae | 8 |
| Carex buxbaumii | Wahlenb. | Cyperaceae | 8 |
| Carex canescens | L. | Cyperaceae | 8 |
| Carex chalciolepis | Holm | Cyperaceae | 8 |
| Carex crawei | Dewey ex Torr. | Cyperaceae | 8 |
| Carex deflexa | Hornem. | Cyperaceae | 8 |
| Carex diandra | Schrank | Cyperaceae | 8 |
| Carex disperma | Dewey | Cyperaceae | 8 |
| Carex douglasii | Boott | Cyperaceae | 8 |
| Carex duriuscula | C.A.Mey. | Cyperaceae | 8 |
| Carex ebenea | Rydb. | Cyperaceae | 8 |
| Carex echinata | Murray | Cyperaceae | 8 |
| Carex elynoides | Holm | Cyperaceae | 8 |
| Carex emoryi | Dewey | Cyperaceae | 8 |
| Carex filifolia | Nutt. | Cyperaceae | 8 |
| Carex haydeniana | Olney | Cyperaceae | 8 |
| Carex hystericina | Muhl. ex Willd. | Cyperaceae | 8 |
| Carex interior | L.H.Bailey | Cyperaceae | 8 |
| Carex kelloggii | W.Boott | Cyperaceae | 8 |
| Carex meadii | Dewey | Cyperaceae | 8 |
| Carex microdonta | Torr. | Cyperaceae | 8 |
| Carex microptera | Mack. | Cyperaceae | 8 |
| Carex occidentalis | L.H.Bailey | Cyperaceae | 8 |
| Carex pachystachya | Cham. ex Steud. | Cyperaceae | 8 |
| Carex pellita | Muhl. ex Willd. | Cyperaceae | 8 |
| Carex petasata | Dewey | Cyperaceae | 8 |
| Carex praegracilis | W.Boott | Cyperaceae | 8 |
| Carex rossii | Boott | Cyperaceae | 8 |
| Carex scoparia | Schkuhr ex Willd. | Cyperaceae | 8 |
| Carex senta | Boott | Cyperaceae | 8 |
| Carex serratodens | S.Watson | Cyperaceae | 8 |
| Carex siccata | Dewey | Cyperaceae | 8 |
| Carex stevenii | (Holm) Kalela | Cyperaceae | 8 |
| Carex stipata | Muhl. ex Willd. | Cyperaceae | 8 |
| Carex subfusca | W.Boott | Cyperaceae | 8 |
| Carex utriculata | Boott | Cyperaceae | 8 |
| Carex vallicola | Dewey | Cyperaceae | 8 |
| Carex vesicaria | L. | Cyperaceae | 8 |
| Carex vulpinoidea | Michx. | Cyperaceae | 8 |
| Carlowrightia arizonica | A.Gray | Acanthaceae | 8 |
| Carlowrightia linearifolia | (Torr.) A.Gray | Acanthaceae | 8 |
| Carminatia tenuiflora | DC. | Asteraceae | 8 |
| Carnegiea gigantea | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Carphochaete bigelovii | A.Gray | Asteraceae | 8 |
| Castela emoryi | (A.Gray) Moran & Felger | Simaroubaceae | 8 |
| Castilleja attenuata | (A.Gray) T.I.Chuang & Heckard | Orobanchaceae | 8 |
| Castilleja chromosa | A.Nelson | Orobanchaceae | 8 |
| Castilleja exserta | (A.Heller) T.I.Chuang & Heckard | Orobanchaceae | 8 |
| Castilleja integra | A.Gray | Orobanchaceae | 8 |
| Castilleja lanata | A.Gray | Orobanchaceae | 8 |
| Castilleja linariifolia | Benth. | Orobanchaceae | 8 |
| Castilleja miniata | Douglas ex Benth. | Orobanchaceae | 8 |
| Castilleja minor | (A.Gray) A.Gray | Orobanchaceae | 8 |
| Castilleja mogollonica | Pennell | Orobanchaceae | 8 |
| Castilleja nelsonii | Eastw. | Orobanchaceae | 8 |
| Castilleja patriotica | Fernald | Orobanchaceae | 8 |
| Castilleja scabrida | Eastw. | Orobanchaceae | 8 |
| Castilleja sessiliflora | Pursh | Orobanchaceae | 8 |
| Castilleja tenuiflora | Benth. | Orobanchaceae | 8 |
| Catabrosa aquatica | (L.) P.Beauv. | Poaceae | 8 |
| Ceanothus fendleri | A.Gray | Rhamnaceae | 8 |
| Ceanothus pauciflorus | DC. | Rhamnaceae | 8 |
| Celtis pallida | Torr. | Cannabaceae | 8 |
| Celtis reticulata | Torr. | Cannabaceae | 8 |
| Cenchrus echinatus | L. | Poaceae | 8 |
| Cenchrus spinifex | Cav. | Poaceae | 8 |
| Centromadia pungens | Greene | Asteraceae | 8 |
| Cephalanthus occidentalis | L. | Rubiaceae | 8 |
| Cerastium beeringianum | Cham. & Schltdl. | Caryophyllaceae | 8 |
| Cerastium brachypodum | (Engelm. ex A.Gray) B.L.Rob. | Caryophyllaceae | 8 |
| Cerastium nutans | Raf. | Caryophyllaceae | 8 |
| Ceratophyllum demersum | L. | Ceratophyllaceae | 8 |
| Cercis orbiculata | Greene | Fabaceae | 8 |
| Cercocarpus betuloides | Nutt. | Rosaceae | 8 |
| Cercocarpus breviflorus | A.Gray | Rosaceae | 8 |
| Cercocarpus intricatus | S.Watson | Rosaceae | 8 |
| Cercocarpus ledifolius | Nutt. | Rosaceae | 8 |
| Cercocarpus montanus | Raf. | Rosaceae | 8 |
| Cevallia sinuata | Lag. | Loasaceae | 8 |
| Chaenactis carphoclinia | A.Gray | Asteraceae | 8 |
| Chaenactis douglasii | Hook. & Arn. | Asteraceae | 8 |
| Chaenactis fremontii | A.Gray | Asteraceae | 8 |
| Chaenactis macrantha | D.C.Eaton | Asteraceae | 8 |
| Chaenactis stevioides | Hook. & Arn. | Asteraceae | 8 |
| Chaenactis xantiana | A.Gray | Asteraceae | 8 |
| Chaetopappa ericoides | (Torr.) G.L.Nesom | Asteraceae | 8 |
| Chamaebatiaria millefolium | (Torr.) Maxim. | Rosaceae | 8 |
| Chamaechaenactis scaposa | Rydb. | Asteraceae | 8 |
| Chamaecrista absus | (L.) H.S.Irwin & Barneby | Fabaceae | 8 |
| Chamaecrista nictitans | (L.) Moench | Fabaceae | 8 |
| Chamaesaracha coronopus | (Dunal) A.Gray | Solanaceae | 8 |
| Chasmanthium latifolium | (Michx.) H.O.Yates | Poaceae | 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 |
| Chenopodium rubrum | L. | Chenopodiaceae | 8 |
| Cherleria obtusiloba | (Rydb.) A.J.Moore & Dillenb. | Caryophyllaceae | 8 |
| Chilopsis linearis | (Cav.) Sweet | Bignoniaceae | 8 |
| Chimaphila maculata | (L.) Pursh | Ericaceae | 8 |
| Chimaphila umbellata | (L.) W.P.C.Barton | Ericaceae | 8 |
| Chloracantha spinosa | (Benth.) G.L.Nesom | Asteraceae | 8 |
| Chloris cucullata | Bisch. | Poaceae | 8 |
| Chloris verticillata | Nutt. | Poaceae | 8 |
| Chloris virgata | Sw. | Poaceae | 8 |
| Choisya dumosa | (Torr. & A.Gray) A.Gray | Rutaceae | 8 |
| Chorizanthe brevicornu | Torr. | Polygonaceae | 8 |
| Chorizanthe corrugata | (Torr.) Torr. & A.Gray | Polygonaceae | 8 |
| Chorizanthe rigida | (Torr.) Torr. & A.Gray | Polygonaceae | 8 |
| Chorizanthe watsonii | Torr. & A.Gray | Polygonaceae | 8 |
| Chrysothamnus depressus | Nutt. | Asteraceae | 8 |
| Chrysothamnus greenei | (A.Gray) Greene | Asteraceae | 8 |
| Chrysothamnus viscidiflorus | Nutt. | 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 brevipes | (A.Gray) Small | Onagraceae | 8 |
| Chylismia cardiophylla | (Torr.) Small | Onagraceae | 8 |
| Chylismia claviformis | (Torr. & Frém.) A.Heller | Onagraceae | 8 |
| Chylismia scapoidea | (Torr. & A.Gray) Small | Onagraceae | 8 |
| Chylismia walkeri | A.Nelson | Onagraceae | 8 |
| Chylismiella pterosperma | (S.Watson) W.L.Wagner & Hoch | Onagraceae | 8 |
| Cicuta maculata | L. | Apiaceae | 8 |
| Cinna latifolia | (Trevir. ex Göpp.) Griseb. | Poaceae | 8 |
| Circaea alpina | L. | Onagraceae | 8 |
| Cirsium arizonicum | (A.Gray) Petr. | Asteraceae | 8 |
| Cirsium mohavense | (Greene) Petr. | Asteraceae | 8 |
| Cirsium neomexicanum | A.Gray | Asteraceae | 8 |
| Cirsium parryi | Petr. | Asteraceae | 8 |
| Cirsium scariosum | Nutt. | Asteraceae | 8 |
| Cirsium undulatum | (Nutt.) Spreng. | Asteraceae | 8 |
| Cirsium wheeleri | Petr. | Asteraceae | 8 |
| Cissus trifoliata | (L.) L. | Vitaceae | 8 |
| Cistanthe monandra | (Nutt.) Hershk. | Montiaceae | 8 |
| Cladium mariscus | (L.) Pohl | Cyperaceae | 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 |
| Claytonia lanceolata | Pursh | Montiaceae | 8 |
| Claytonia parviflora | Douglas | Montiaceae | 8 |
| Claytonia perfoliata | Donn ex Willd. | Montiaceae | 8 |
| Claytonia rosea | Rydb. | Montiaceae | 8 |
| Clematis columbiana | (Nutt.) Torr. & A.Gray | Ranunculaceae | 8 |
| Clematis drummondii | Torr. & A.Gray | Ranunculaceae | 8 |
| Clematis hirsutissima | Pursh | Ranunculaceae | 8 |
| Clematis ligusticifolia | Nutt. | Ranunculaceae | 8 |
| Cleome dodecandra | L. | Cleomaceae | 8 |
| Cleomella arborea | (Nutt.) Roalson & J.C.Hall | Cleomaceae | 8 |
| Cleomella longipes | Torr. | 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 |
| Cleomella serrulata | (Pursh) Roalson & J.C.Hall | Cleomaceae | 8 |
| Clitoria mariana | L. | Fabaceae | 8 |
| Cnidoscolus angustidens | Torr. | Euphorbiaceae | 8 |
| Cochemiea grahamii | (Engelm.) Doweld | Cactaceae | 8 |
| Cochemiea sheldonii | (Britton & Rose) Doweld | Cactaceae | 8 |
| Coleogyne ramosissima | Torr. | Rosaceae | 8 |
| Collinsia parviflora | Douglas ex Lindl. | Plantaginaceae | 8 |
| Collomia debilis | Greene | Polemoniaceae | 8 |
| Collomia grandiflora | Douglas ex Lindl. | Polemoniaceae | 8 |
| Collomia linearis | Nutt. | Polemoniaceae | 8 |
| Cologania angustifolia | Kunth | Fabaceae | 8 |
| Cologania obovata | Schltdl. | Fabaceae | 8 |
| Colubrina californica | I.M.Johnst. | Rhamnaceae | 8 |
| Comandra umbellata | (L.) Nutt. | Santalaceae | 8 |
| Comastoma tenellum | (Rottb.) Toyok. | Gentianaceae | 8 |
| Commelina dianthifolia | Redouté | Commelinaceae | 8 |
| Commelina erecta | L. | Commelinaceae | 8 |
| Condalia correllii | M.C.Johnst. | Rhamnaceae | 8 |
| Condalia ericoides | (A.Gray) M.C.Johnst. | Rhamnaceae | 8 |
| Condalia globosa | I.M.Johnst. | Rhamnaceae | 8 |
| Condea emoryi | (Torr.) Harley & J.F.B.Pastore | Lamiaceae | 8 |
| Conioselinum scopulorum | (A.Gray) J.M.Coult. & Rose | Apiaceae | 8 |
| Conoclinium greggii | Small | Asteraceae | 8 |
| Conopholis alpina | Liebm. | Orobanchaceae | 8 |
| Convolvulus equitans | Benth. | Convolvulaceae | 8 |
| Convolvulus simulans | L.M.Perry | Convolvulaceae | 8 |
| Corallorhiza maculata | Raf. | Orchidaceae | 8 |
| Corallorhiza striata | Lindl. | Orchidaceae | 8 |
| Corallorhiza wisteriana | Conrad | Orchidaceae | 8 |
| Cordia parvifolia | A.DC. | Cordiaceae | 8 |
| Cordylanthus nevinii | A.Gray | Orobanchaceae | 8 |
| Cordylanthus wrightii | A.Gray | Orobanchaceae | 8 |
| Coreocarpus arizonicus | S.F.Blake | Asteraceae | 8 |
| Coreopsis californica | (Nutt.) H.Sharsm. | Asteraceae | 8 |
| Coreopsis tinctoria | Nutt. | Asteraceae | 8 |
| Cornus sericea | L. | Cornaceae | 8 |
| Corydalis aurea | Willd. | Papaveraceae | 8 |
| Coryphantha robustispina | (Schott ex Engelm.) Britton & Rose | Cactaceae | 8 |
| Cottea pappophoroides | Kunth | Poaceae | 8 |
| Cottsia gracilis | (A.Gray) W.R.Anderson & C.Davis | Malpighiaceae | 8 |
| Coursetia caribaea | (Jacq.) Lavin | Fabaceae | 8 |
| Coursetia glandulosa | A.Gray | Fabaceae | 8 |
| Crassula connata | A.Berger | Crassulaceae | 8 |
| Crataegus macracantha | (Lindl.) Lodd. ex Loudon | Rosaceae | 8 |
| Crataegus rivularis | Nutt. | Rosaceae | 8 |
| Crepis acuminata | Nutt. | Asteraceae | 8 |
| Crepis intermedia | A.Gray | Asteraceae | 8 |
| Crepis occidentalis | Nutt. | Asteraceae | 8 |
| Cressa truxillensis | Kunth | Convolvulaceae | 8 |
| Crossosoma bigelovii | S.Watson | Crossosomataceae | 8 |
| Crotalaria pumila | Ortega | Fabaceae | 8 |
| Crotalaria sagittalis | L. | Fabaceae | 8 |
| Croton californicus | Müll.Arg. | Euphorbiaceae | 8 |
| Croton ciliatoglandulifer | Ortega | Euphorbiaceae | 8 |
| Croton fruticulosus | Torr. | Euphorbiaceae | 8 |
| Croton lindheimerianus | Scheele | Euphorbiaceae | 8 |
| Croton monanthogynus | Michx. | Euphorbiaceae | 8 |
| Croton pottsii | (Klotzsch) Müll.Arg. | Euphorbiaceae | 8 |
| Croton sonorae | Torr. | Euphorbiaceae | 8 |
| Croton texensis | (Klotzsch) Müll.Arg. | Euphorbiaceae | 8 |
| Croton wigginsii | L.C.Wheeler | Euphorbiaceae | 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 dumetorum | (Greene ex A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha fendleri | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha gracilis | Osterh. | Boraginaceae | 8 |
| Cryptantha intermedia | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha maritima | (Greene) Greene | Boraginaceae | 8 |
| Cryptantha minima | Rydb. | Boraginaceae | 8 |
| Cryptantha nevadensis | A.Nelson & P.B.Kenn. | Boraginaceae | 8 |
| Cryptantha pterocarya | (Torr.) Greene | Boraginaceae | 8 |
| Cryptantha recurvata | Coville | Boraginaceae | 8 |
| Cryptantha utahensis | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptogramma acrostichoides | R.Br. | Pteridaceae | 8 |
| Cucurbita digitata | A.Gray | Cucurbitaceae | 8 |
| Cucurbita foetidissima | Kunth | Cucurbitaceae | 8 |
| Cucurbita palmata | S.Watson | Cucurbitaceae | 8 |
| Cuphea wrightii | A.Gray | Lythraceae | 8 |
| Cuscuta californica | Hook. & Arn. | Convolvulaceae | 8 |
| Cuscuta campestris | Yunck. | Convolvulaceae | 8 |
| Cuscuta cephalanthi | Engelm. | Convolvulaceae | 8 |
| Cuscuta coryli | Engelm. | Convolvulaceae | 8 |
| Cuscuta denticulata | Engelm. | Convolvulaceae | 8 |
| Cuscuta gronovii | Willd. | Convolvulaceae | 8 |
| Cuscuta indecora | Choisy | Convolvulaceae | 8 |
| Cuscuta tuberculata | Brandegee | Convolvulaceae | 8 |
| Cuscuta umbellata | Kunth | Convolvulaceae | 8 |
| Cycladenia humilis | Benth. | Apocynaceae | 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 echinocarpa | (Engelm. & J.M.Bigelow) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia fulgida | (Engelm.) F.M.Knuth | 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 multigeniculata | (Clokey) Backeb. | Cactaceae | 8 |
| Cylindropuntia ramosissima | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia thurberi | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia whipplei | (Engelm. & J.M.Bigelow) F.M.Knuth | Cactaceae | 8 |
| Cymopterus alpinus | A.Gray | Apiaceae | 8 |
| Cymopterus glomeratus | (Nutt.) DC. | Apiaceae | 8 |
| Cymopterus lemmonii | (J.M.Coult. & Rose) Dorn | Apiaceae | 8 |
| Cymopterus petraeus | M.E.Jones | Apiaceae | 8 |
| Cymopterus purpureus | S.Watson | Apiaceae | 8 |
| Cymopterus sessiliflorus | (W.L.Theob. & C.C.Tseng) R.L.Hartm. | Apiaceae | 8 |
| Cyperus acuminatus | Torr. & Hook. | Cyperaceae | 8 |
| Cyperus aggregatus | (Willd.) Endl. | Cyperaceae | 8 |
| Cyperus bipartitus | Torr. | Cyperaceae | 8 |
| Cyperus esculentus | L. | Cyperaceae | 8 |
| Cyperus fendlerianus | Boeckeler | Cyperaceae | 8 |
| Cyperus hermaphroditus | (Jacq.) Standl. | Cyperaceae | 8 |
| Cyperus laevigatus | L. | Cyperaceae | 8 |
| Cyperus manimae | Kunth | Cyperaceae | 8 |
| Cyperus melanostachyus | Kunth | Cyperaceae | 8 |
| Cyperus odoratus | L. | Cyperaceae | 8 |
| Cyperus retroflexus | Buckley | Cyperaceae | 8 |
| Cyperus seslerioides | Kunth | Cyperaceae | 8 |
| Cyperus sphaerolepis | Boeckeler | Cyperaceae | 8 |
| Cyperus squarrosus | L. | Cyperaceae | 8 |
| Cyperus strigosus | L. | Cyperaceae | 8 |
| Cyperus subsquarrosus | (Muhl.) Bauters | Cyperaceae | 8 |
| Cyperus tetragonus | Elliott | Cyperaceae | 8 |
| Cypripedium parviflorum | Salisb. | Orchidaceae | 8 |
| Cystopteris bulbifera | (L.) Bernh. | Cystopteridaceae | 8 |
| Cystopteris fragilis | (L.) Bernh. | Cystopteridaceae | 8 |
| Cystopteris reevesiana | Lellinger | Cystopteridaceae | 8 |
| Cystopteris tenuis | (Michx.) Desv. | Cystopteridaceae | 8 |
| Dalea albiflora | A.Gray | Fabaceae | 8 |
| Dalea aurea | Nutt. ex Pursh | Fabaceae | 8 |
| Dalea candida | Willd. | Fabaceae | 8 |
| Dalea formosa | Torr. | Fabaceae | 8 |
| Dalea jamesii | (Torr.) Torr. & A.Gray | Fabaceae | 8 |
| Dalea lanata | Spreng. | Fabaceae | 8 |
| Dalea leporina | (Aiton) Bullock | Fabaceae | 8 |
| Dalea mollis | Benth. | Fabaceae | 8 |
| Dalea mollissima | (Rydb.) Munz | Fabaceae | 8 |
| Dalea nana | Torr. ex A.Gray | Fabaceae | 8 |
| Dalea neomexicana | (A.Gray) Cory | Fabaceae | 8 |
| Dalea phleoides | (Torr. & A.Gray) Shinners | 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 purpurea | Vent. | Fabaceae | 8 |
| Dalea rubescens | S.Watson | Fabaceae | 8 |
| Dalea searlsiae | (A.Gray) Barneby | Fabaceae | 8 |
| Dalea urceolata | Greene | Fabaceae | 8 |
| Dalea versicolor | Zucc. | Fabaceae | 8 |
| Dalea wrightii | A.Gray | Fabaceae | 8 |
| Danthonia californica | Bol. | Poaceae | 8 |
| Danthonia intermedia | Vasey | Poaceae | 8 |
| Danthonia spicata | (L.) Roem. & Schult. | Poaceae | 8 |
| Dasiphora fruticosa | (L.) Rydb. | Rosaceae | 8 |
| Dasylirion wheeleri | S.Watson ex Rothr. | Asparagaceae | 8 |
| Datura discolor | Bernh. | Solanaceae | 8 |
| Daucus pusillus | Michx. | Apiaceae | 8 |
| Deinandra kelloggii | Greene | Asteraceae | 8 |
| Delphinium barbeyi | (Huth) Huth | Ranunculaceae | 8 |
| Delphinium geraniifolium | Rydb. | Ranunculaceae | 8 |
| Delphinium nuttallianum | Pritz. | Ranunculaceae | 8 |
| Delphinium parishii | A.Gray | Ranunculaceae | 8 |
| Delphinium scaposum | Greene | Ranunculaceae | 8 |
| Delphinium scopulorum | A.Gray | Ranunculaceae | 8 |
| Delphinium wootonii | Rydb. | Ranunculaceae | 8 |
| Deschampsia danthonioides | (Trin.) Benth. | Poaceae | 8 |
| Deschampsia elongata | (Hook.) Munro | Poaceae | 8 |
| Descurainia californica | (A.Gray) O.E.Schulz | Brassicaceae | 8 |
| Descurainia incisa | (Engelm.) Britton | Brassicaceae | 8 |
| Descurainia longepedicellata | (E.Fourn.) O.E.Schulz | Brassicaceae | 8 |
| Descurainia pinnata | (Walter) Britton | Brassicaceae | 8 |
| Desmanthus bicornutus | S.Watson | Fabaceae | 8 |
| Desmanthus cooleyi | (Eaton) Trel. ex Branner & Coville | Fabaceae | 8 |
| Desmodium batocaulon | A.Gray | Fabaceae | 8 |
| Desmodium grahamii | A.Gray | Fabaceae | 8 |
| Desmodium illinoense | A.Gray | Fabaceae | 8 |
| Desmodium intortum | (Mill.) Urb. | Fabaceae | 8 |
| Desmodium nuttallii | (Schindl.) B.G.Schub. | Fabaceae | 8 |
| Desmodium procumbens | (Mill.) C.L.Hitchc. | Fabaceae | 8 |
| Desmodium psilophyllum | Schltdl. | Fabaceae | 8 |
| Desmodium rosei | B.G.Schub. | Fabaceae | 8 |
| Desmodium scorpiurus | (Sw.) Poir. | Fabaceae | 8 |
| Dianthera candicans | (Nees) Benth. & Hook.f. ex Hemsl. | Acanthaceae | 8 |
| Diaperia verna | (Raf.) Morefield | Asteraceae | 8 |
| Dichanthelium lanuginosum | (Elliott) Gould | Poaceae | 8 |
| Dichelostemma capitatum | (Benth.) Alph.Wood | Asparagaceae | 8 |
| Dichondra argentea | Humb. & Bonpl. ex Willd. | Convolvulaceae | 8 |
| Dichondra brachypoda | Wooton & Standl. | Convolvulaceae | 8 |
| Dichondra sericea | Sw. | Convolvulaceae | 8 |
| Dichromanthus michuacanus | (La Llave & Lex.) Salazar & Soto Arenas | Orchidaceae | 8 |
| Dicliptera resupinata | (Vahl) Juss. | Acanthaceae | 8 |
| Dicoria canescens | A.Gray | Asteraceae | 8 |
| Dieteria asteroides | Torr. | Asteraceae | 8 |
| Dieteria bigelovii | (A.Gray) D.R.Morgan & R.L.Hartm. | Asteraceae | 8 |
| Dieteria canescens | (Pursh) Nutt. | Asteraceae | 8 |
| Digitaria californica | (Benth.) Henrard | Poaceae | 8 |
| Digitaria insularis | (L.) Mez ex Ekman | Poaceae | 8 |
| Diplachne fusca | (L.) P.Beauv. | Poaceae | 8 |
| Diplacus bigelovii | (A.Gray) G.L.Nesom | Phrymaceae | 8 |
| Diplacus parryi | (A.Gray) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Disakisperma dubium | (Kunth) P.M.Peterson & N.Snow | Poaceae | 8 |
| Distichlis spicata | (L.) Greene | Poaceae | 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 |
| Dodonaea viscosa | Jacq. | Sapindaceae | 8 |
| Draba albertina | Greene | Brassicaceae | 8 |
| Draba asprella | Greene | Brassicaceae | 8 |
| Draba aurea | Vahl ex Hornem. | Brassicaceae | 8 |
| Draba helleriana | Greene | Brassicaceae | 8 |
| Draba mogollonica | Greene | Brassicaceae | 8 |
| Draba petrophila | Greene | Brassicaceae | 8 |
| Dracocephalum parviflorum | Nutt. | Lamiaceae | 8 |
| Drymaria glandulosa | Bartl. | Caryophyllaceae | 8 |
| Drymaria leptophylla | (Cham. & Schltdl.) Fenzl ex Rohrb. | Caryophyllaceae | 8 |
| Drymaria molluginea | (Ser.) Didr. | Caryophyllaceae | 8 |
| Drymocallis glandulosa | (Lindl.) Rydb. | Rosaceae | 8 |
| Dryopetalon runcinatum | A.Gray | Brassicaceae | 8 |
| Dryopteris filix-mas | (L.) Schott | Dryopteridaceae | 8 |
| Dudleya arizonica | Rose | Crassulaceae | 8 |
| Dudleya saxosa | (M.E.Jones) Britton & Rose | Crassulaceae | 8 |
| Dyschoriste decumbens | (A.Gray) Kuntze | Acanthaceae | 8 |
| Dyssodia papposa | (Vent.) Hitchc. | Asteraceae | 8 |
| Echeandia flavescens | (Schult. & Schult.f.) Cruden | Asparagaceae | 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 santaritensis | W.Blum & Rutow | Cactaceae | 8 |
| Echinocereus yavapaiensis | M.A.Baker | Cactaceae | 8 |
| Echinochloa muricata | (P.Beauv.) Fernald | Poaceae | 8 |
| Echinocystis lobata | (Michx.) Torr. & A.Gray | Cucurbitaceae | 8 |
| Echinopepon wrightii | (A.Gray) S.Watson | Cucurbitaceae | 8 |
| Eclipta prostrata | (L.) L. | Asteraceae | 8 |
| Elatine americana | (Pursh) Arn. | Elatinaceae | 8 |
| Elatine brachysperma | A.Gray | Elatinaceae | 8 |
| Eleocharis acicularis | (L.) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis atropurpurea | (Retz.) J.Presl & C.Presl | Cyperaceae | 8 |
| Eleocharis engelmannii | Steud. | Cyperaceae | 8 |
| Eleocharis erythropoda | Steud. | 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 ovata | (Roth) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis palustris | (L.) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis quinqueflora | (Hartmann) O.Schwarz | Cyperaceae | 8 |
| Eleocharis rostellata | (Torr.) Torr. | Cyperaceae | 8 |
| Elymus canadensis | L. | Poaceae | 8 |
| Elymus elymoides | (Raf.) Swezey | Poaceae | 8 |
| Elymus glaucus | Buckley | Poaceae | 8 |
| Elymus interruptus | Buckley | Poaceae | 8 |
| Elymus lanceolatus | (Scribn. & J.G.Sm.) Gould | Poaceae | 8 |
| Elymus longifolius | (J.G.Sm.) Gould | Poaceae | 8 |
| Elymus multisetus | (J.G.Sm.) Burtt Davy | Poaceae | 8 |
| Elymus scribneri | (Vasey) M.E.Jones | Poaceae | 8 |
| Elymus smithii | (Rydb.) Gould | Poaceae | 8 |
| Elymus violaceus | (Hornem.) J.Feilberg | Poaceae | 8 |
| Elymus virginicus | L. | Poaceae | 8 |
| Elytraria imbricata | (Vahl) Pers. | Acanthaceae | 8 |
| Emmenanthe penduliflora | Benth. | Hydrophyllaceae | 8 |
| Encelia farinosa | A.Gray ex Torr. | Asteraceae | 8 |
| Encelia frutescens | A.Gray | Asteraceae | 8 |
| Encelia resinifera | C.Clark | Asteraceae | 8 |
| Encelia virginensis | A.Nelson | Asteraceae | 8 |
| Enceliopsis argophylla | A.Nelson | Asteraceae | 8 |
| Enceliopsis nudicaulis | A.Nelson | Asteraceae | 8 |
| Engelmannia peristenia | (Raf.) Goodman & C.A.Lawson | Asteraceae | 8 |
| Enneapogon desvauxii | P.Beauv. | Poaceae | 8 |
| Ephedra aspera | Engelm. ex S.Watson | Ephedraceae | 8 |
| Ephedra cutleri | Peebles | Ephedraceae | 8 |
| Ephedra nevadensis | S.Watson | Ephedraceae | 8 |
| Ephedra torreyana | S.Watson | Ephedraceae | 8 |
| Ephedra trifurca | Torr. ex S.Watson | Ephedraceae | 8 |
| Ephedra viridis | Coville | Ephedraceae | 8 |
| Epilobium angustifolium | L. | Onagraceae | 8 |
| Epilobium brachycarpum | C.Presl | Onagraceae | 8 |
| Epilobium canum | (Greene) P.H.Raven | Onagraceae | 8 |
| Epilobium ciliatum | Raf. | Onagraceae | 8 |
| Epilobium densiflorum | (Lindl.) Hoch & P.H.Raven | Onagraceae | 8 |
| Epilobium hornemannii | Rchb. | Onagraceae | 8 |
| Epilobium lactiflorum | Hausskn. | Onagraceae | 8 |
| Epipactis gigantea | Douglas | Orchidaceae | 8 |
| Epithelantha micromeris | (Engelm.) F.A.C.Weber ex Britton & Rose | Cactaceae | 8 |
| Epixiphium wislizeni | (Engelm. ex A.Gray) Munz | Plantaginaceae | 8 |
| Equisetum arvense | L. | Equisetaceae | 8 |
| Equisetum hyemale | L. | Equisetaceae | 8 |
| Equisetum laevigatum | A.Braun | Equisetaceae | 8 |
| Eragrostis intermedia | Hitchc. | Poaceae | 8 |
| Eragrostis pectinacea | (Michx.) Nees | Poaceae | 8 |
| Eragrostis spectabilis | (Pursh) Steud. | Poaceae | 8 |
| Eremalche exilis | (A.Gray) Greene | Malvaceae | 8 |
| Eremalche rotundifolia | (A.Gray) Greene | Malvaceae | 8 |
| Eremocarya micrantha | (Torr.) Greene | Boraginaceae | 8 |
| Eremocrinum albomarginatum | (M.E.Jones) M.E.Jones | Asparagaceae | 8 |
| Eremogone eastwoodiae | (Rydb.) Ikonn. | Caryophyllaceae | 8 |
| Eremogone fendleri | (A.Gray) Ikonn. | Caryophyllaceae | 8 |
| Eremogone ferrisiae | (Abrams) R.L.Hartm. & Rabeler | Caryophyllaceae | 8 |
| Eremogone macradenia | (S.Watson) Ikonn. | Caryophyllaceae | 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 diffusum | (A.Gray) H.Mason | Polemoniaceae | 8 |
| Eriastrum eremicum | (Jeps.) H.Mason | Polemoniaceae | 8 |
| Ericameria brachylepis | 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 parryi | (A.Gray) G.L.Nesom & G.I.Baird | Asteraceae | 8 |
| Ericameria teretifolia | Jeps. | Asteraceae | 8 |
| Erigeron aphanactis | Greene | Asteraceae | 8 |
| Erigeron arizonicus | A.Gray | Asteraceae | 8 |
| Erigeron bellidiastrum | Nutt. | Asteraceae | 8 |
| Erigeron canadensis | L. | Asteraceae | 8 |
| Erigeron compositus | Pursh | Asteraceae | 8 |
| Erigeron concinnus | Torr. & A.Gray | Asteraceae | 8 |
| Erigeron divergens | Torr. & A.Gray | Asteraceae | 8 |
| Erigeron eatonii | A.Gray | Asteraceae | 8 |
| Erigeron flagellaris | A.Gray | Asteraceae | 8 |
| Erigeron formosissimus | Greene | Asteraceae | 8 |
| Erigeron lonchophyllus | Hook. | 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 tener | A.Gray | Asteraceae | 8 |
| Erigeron tracyi | Greene | Asteraceae | 8 |
| Erigeron ursinus | D.C.Eaton | Asteraceae | 8 |
| Erigeron utahensis | A.Gray | Asteraceae | 8 |
| Erigeron wislizeni | (A.Gray) Greene | Asteraceae | 8 |
| Eriochloa contracta | Hitchc. | Poaceae | 8 |
| Eriocoma arida | (M.E.Jones) Romasch. | Poaceae | 8 |
| Eriocoma hymenoides | (Roem. & Schult.) Rydb. | Poaceae | 8 |
| Eriocoma nelsonii | (Scribn.) Romasch. | Poaceae | 8 |
| Eriocoma occidentalis | (Thurb. ex S.Watson) Romasch. | Poaceae | 8 |
| Eriocoma parishii | (Vasey) Romasch. | Poaceae | 8 |
| Eriocoma pinetorum | (M.E.Jones) Romasch. | Poaceae | 8 |
| Eriodictyon angustifolium | Nutt. | Namaceae | 8 |
| Eriogonum abertianum | Torr. | Polygonaceae | 8 |
| Eriogonum alatum | Torr. | Polygonaceae | 8 |
| Eriogonum arcuatum | Greene | Polygonaceae | 8 |
| Eriogonum brachypodum | Torr. & A.Gray | Polygonaceae | 8 |
| Eriogonum caespitosum | Nutt. | Polygonaceae | 8 |
| Eriogonum cernuum | Nutt. | Polygonaceae | 8 |
| Eriogonum corymbosum | Benth. | Polygonaceae | 8 |
| Eriogonum davidsonii | Greene | Polygonaceae | 8 |
| Eriogonum deflexum | Torr. | Polygonaceae | 8 |
| Eriogonum deserticola | S.Watson | Polygonaceae | 8 |
| Eriogonum exaltatum | M.E.Jones | Polygonaceae | 8 |
| Eriogonum fasciculatum | Benth. | Polygonaceae | 8 |
| Eriogonum heermannii | Durand & Hilg. | Polygonaceae | 8 |
| Eriogonum hookeri | S.Watson | Polygonaceae | 8 |
| Eriogonum inflatum | Torr. & Frém. | Polygonaceae | 8 |
| Eriogonum jamesii | Benth. | Polygonaceae | 8 |
| Eriogonum lachnogynum | Torr. ex Benth. | Polygonaceae | 8 |
| Eriogonum leptophyllum | Wooton & Standl. | Polygonaceae | 8 |
| Eriogonum maculatum | A.Heller | Polygonaceae | 8 |
| Eriogonum nidularium | Coville | Polygonaceae | 8 |
| Eriogonum nummulare | M.E.Jones | Polygonaceae | 8 |
| Eriogonum ovalifolium | Nutt. | Polygonaceae | 8 |
| Eriogonum palmerianum | Reveal | Polygonaceae | 8 |
| Eriogonum panamintense | C.V.Morton | Polygonaceae | 8 |
| Eriogonum plumatella | Durand & Hilg. | Polygonaceae | 8 |
| Eriogonum polycladon | Benth. | Polygonaceae | 8 |
| Eriogonum pusillum | Torr. & A.Gray | Polygonaceae | 8 |
| Eriogonum racemosum | Nutt. | Polygonaceae | 8 |
| Eriogonum reniforme | Torr. & Frém. | Polygonaceae | 8 |
| Eriogonum rotundifolium | Benth. | Polygonaceae | 8 |
| Eriogonum shockleyi | S.Watson | Polygonaceae | 8 |
| Eriogonum thomasii | Torr. | Polygonaceae | 8 |
| Eriogonum thurberi | Torr. | Polygonaceae | 8 |
| Eriogonum trichopes | Torr. | Polygonaceae | 8 |
| Eriogonum umbellatum | Torr. | Polygonaceae | 8 |
| Eriogonum wrightii | Torr. ex Benth. | Polygonaceae | 8 |
| Erioneuron avenaceum | (Kunth) Tateoka | Poaceae | 8 |
| Erioneuron pilosum | (Buckley) Nash | Poaceae | 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 |
| Eryngium heterophyllum | Engelm. | Apiaceae | 8 |
| Eryngium lemmonii | J.M.Coult. & Rose | Apiaceae | 8 |
| Eryngium nasturtiifolium | F.Delaroche | Apiaceae | 8 |
| Erythranthe breweri | (Greene) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythranthe cinnabarina | G.L.Nesom | Phrymaceae | 8 |
| Erythranthe cordata | (Greene) G.L.Nesom | 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 guttata | (DC.) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe minor | (A.Nelson) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe nasuta | (Greene) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe primuloides | (Benth.) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythranthe rubella | (A.Gray) N.S.Fraga | Phrymaceae | 8 |
| Erythranthe suksdorfii | (A.Gray) N.S.Fraga | Phrymaceae | 8 |
| Erythranthe tilingii | (Regel) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe unimaculata | (Pennell) G.L.Nesom | Phrymaceae | 8 |
| Erythranthe verbenacea | (Greene) G.L.Nesom & N.S.Fraga | Phrymaceae | 8 |
| Erythrina flabelliformis | Kearney | Fabaceae | 8 |
| Eschscholzia californica | Cham. | Papaveraceae | 8 |
| Eschscholzia glyptosperma | Greene | Papaveraceae | 8 |
| Eschscholzia minutiflora | S.Watson | Papaveraceae | 8 |
| Eucnide urens | Parry ex Coville | Loasaceae | 8 |
| Eucrypta chrysanthemifolia | (Benth.) Greene | Hydrophyllaceae | 8 |
| Eucrypta micrantha | (Torr.) A.Heller | Hydrophyllaceae | 8 |
| Eulobus californicus | Nutt. ex Torr. & A.Gray | Onagraceae | 8 |
| Euphorbia abramsiana | L.C.Wheeler | Euphorbiaceae | 8 |
| Euphorbia albomarginata | Torr. & A.Gray | Euphorbiaceae | 8 |
| Euphorbia arizonica | Engelm. | Euphorbiaceae | 8 |
| Euphorbia brachycera | Engelm. | Euphorbiaceae | 8 |
| Euphorbia capitellata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia chaetocalyx | (Boiss.) Tidestr. | Euphorbiaceae | 8 |
| Euphorbia chamaesula | Boiss. | Euphorbiaceae | 8 |
| Euphorbia cuphosperma | (Engelm.) Boiss. | Euphorbiaceae | 8 |
| Euphorbia davidii | Subils | Euphorbiaceae | 8 |
| Euphorbia eriantha | Benth. | Euphorbiaceae | 8 |
| Euphorbia exstipulata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia fendleri | Torr. & A.Gray | Euphorbiaceae | 8 |
| Euphorbia florida | Engelm. | Euphorbiaceae | 8 |
| Euphorbia glyptosperma | Engelm. | Euphorbiaceae | 8 |
| Euphorbia gracillima | S.Watson | Euphorbiaceae | 8 |
| Euphorbia hirta | L. | Euphorbiaceae | 8 |
| Euphorbia hyssopifolia | L. | Euphorbiaceae | 8 |
| Euphorbia indivisa | (Engelm.) Tidestr. | Euphorbiaceae | 8 |
| Euphorbia lurida | Engelm. | Euphorbiaceae | 8 |
| Euphorbia macropus | (Klotzsch & Garcke) Boiss. | Euphorbiaceae | 8 |
| Euphorbia maculata | L. | Euphorbiaceae | 8 |
| Euphorbia marginata | Pursh | Euphorbiaceae | 8 |
| Euphorbia melanadenia | Torr. | Euphorbiaceae | 8 |
| Euphorbia micromera | Boiss. | Euphorbiaceae | 8 |
| Euphorbia ocellata | Durand & Hilg. | Euphorbiaceae | 8 |
| Euphorbia parryi | Engelm. | Euphorbiaceae | 8 |
| Euphorbia pediculifera | Engelm. | Euphorbiaceae | 8 |
| Euphorbia polycarpa | Benth. | Euphorbiaceae | 8 |
| Euphorbia prostrata | Aiton | Euphorbiaceae | 8 |
| Euphorbia radians | Benth. | Euphorbiaceae | 8 |
| Euphorbia revoluta | Engelm. | Euphorbiaceae | 8 |
| Euphorbia schizoloba | Engelm. | 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 vermiculata | Raf. | Euphorbiaceae | 8 |
| Euphrosyne dealbata | (A.Gray) Panero | Asteraceae | 8 |
| Euploca convolvulacea | Nutt. | Heliotropiaceae | 8 |
| Euploca procumbens | (Mill.) Diane & Hilger | Heliotropiaceae | 8 |
| Eustoma exaltatum | (L.) Salisb. ex G.Don | Gentianaceae | 8 |
| Euthamia occidentalis | Nutt. | Asteraceae | 8 |
| Eutrochium maculatum | (L.) E.E.Lamont | Asteraceae | 8 |
| Evolvulus alsinoides | (L.) L. | Convolvulaceae | 8 |
| Evolvulus arizonicus | A.Gray | Convolvulaceae | 8 |
| Evolvulus nuttallianus | Schult. | Convolvulaceae | 8 |
| Evolvulus sericeus | Sw. | Convolvulaceae | 8 |
| Eysenhardtia orthocarpa | (A.Gray) S.Watson | 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 emoryi | (Engelm.) Orcutt | Cactaceae | 8 |
| Ferocactus wislizeni | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Festuca arizonica | Vasey | Poaceae | 8 |
| Festuca brachyphylla | Schult. & Schult.f. | Poaceae | 8 |
| Festuca idahoensis | Elmer | Poaceae | 8 |
| Festuca microstachys | Nutt. | Poaceae | 8 |
| Festuca octoflora | Walter | Poaceae | 8 |
| Festuca rubra | L. | Poaceae | 8 |
| Fimbristylis dichotoma | (L.) Vahl | Cyperaceae | 8 |
| Fimbristylis puberula | (Michx.) Vahl | Cyperaceae | 8 |
| Fimbristylis thermalis | S.Watson | Cyperaceae | 8 |
| Fimbristylis vahlii | (Lam.) Link | Cyperaceae | 8 |
| Flaveria trinervia | (Spreng.) C.Mohr | Asteraceae | 8 |
| Flourensia cernua | DC. | Asteraceae | 8 |
| Forestiera pubescens | Nutt. | Oleaceae | 8 |
| Fouquieria splendens | Engelm. | Fouquieriaceae | 8 |
| Fragaria vesca | L. | Rosaceae | 8 |
| Fragaria virginiana | Mill. | Rosaceae | 8 |
| Frangula californica | (Eschsch.) A.Gray | Rhamnaceae | 8 |
| Frangula obovata | (Kearney & Peebles) G.L.Nesom & Sawyer | Rhamnaceae | 8 |
| Frasera albomarginata | S.Watson | Gentianaceae | 8 |
| Frasera paniculata | Torr. | Gentianaceae | 8 |
| Frasera speciosa | Douglas ex Griseb. | Gentianaceae | 8 |
| Fraxinus anomala | Torr. ex S.Watson | Oleaceae | 8 |
| Fraxinus cuspidata | Torr. | Oleaceae | 8 |
| Fraxinus dipetala | Hook. & Arn. | Oleaceae | 8 |
| Fraxinus papillosa | Lingelsh. | Oleaceae | 8 |
| Fraxinus velutina | Torr. | Oleaceae | 8 |
| Fritillaria atropurpurea | Nutt. | Liliaceae | 8 |
| Froelichia arizonica | Thornber ex Standl. | Amaranthaceae | 8 |
| Froelichia gracilis | (Hook.) Moq. | Amaranthaceae | 8 |
| Funastrum crispum | (Benth.) Schltr. | Apocynaceae | 8 |
| Funastrum cynanchoides | (Decne.) Schltr. | Apocynaceae | 8 |
| Funastrum heterophyllum | (Engelm. ex Torr.) Standl. | Apocynaceae | 8 |
| Funastrum utahense | (Engelm.) Liede & Meve | Apocynaceae | 8 |
| Gaillardia multiceps | Greene | Asteraceae | 8 |
| Gaillardia pinnatifida | Torr. | Asteraceae | 8 |
| Gaillardia pulchella | Foug. | Asteraceae | 8 |
| Galactia wrightii | A.Gray | Fabaceae | 8 |
| Galinsoga parviflora | Cav. | Asteraceae | 8 |
| Galium mexicanum | Kunth | Rubiaceae | 8 |
| Galium proliferum | A.Gray | Rubiaceae | 8 |
| Galium stellatum | Kellogg | Rubiaceae | 8 |
| Galium trifidum | L. | Rubiaceae | 8 |
| Galium triflorum | Michx. | Rubiaceae | 8 |
| Galium wrightii | A.Gray | Rubiaceae | 8 |
| Gamochaeta purpurea | (L.) Cabrera | Asteraceae | 8 |
| Gamochaeta stagnalis | (I.M.Johnst.) Anderb. | Asteraceae | 8 |
| Garrya flavescens | S.Watson | Garryaceae | 8 |
| Garrya wrightii | Torr. | Garryaceae | 8 |
| Gayophytum ramosissimum | Torr. & A.Gray | Onagraceae | 8 |
| Gentiana affinis | Griseb. | Gentianaceae | 8 |
| Gentiana parryi | Engelm. | Gentianaceae | 8 |
| Gentianopsis barbellata | (Engelm.) Iltis | Gentianaceae | 8 |
| Geraea canescens | Torr. & A.Gray | Asteraceae | 8 |
| Geranium caespitosum | E.James | Geraniaceae | 8 |
| Geranium carolinianum | L. | Geraniaceae | 8 |
| Geranium lentum | Wooton & Standl. | Geraniaceae | 8 |
| Geranium richardsonii | Fisch. & Trautv. | Geraniaceae | 8 |
| Geranium wislizeni | S.Watson | Geraniaceae | 8 |
| Geum aleppicum | Jacq. | Rosaceae | 8 |
| Geum macrophyllum | Willd. | Rosaceae | 8 |
| Geum rossii | (R.Br.) Ser. | Rosaceae | 8 |
| Geum triflorum | Pursh | Rosaceae | 8 |
| Gilia achilleifolia | Benth. | Polemoniaceae | 8 |
| Gilia capitata | Sims | Polemoniaceae | 8 |
| Gilia clivorum | (Jeps.) V.E.Grant | Polemoniaceae | 8 |
| Gilia clokeyi | H.Mason | 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 ophthalmoides | Brand | Polemoniaceae | 8 |
| Gilia scopulorum | M.E.Jones | Polemoniaceae | 8 |
| Gilia sinuata | Douglas ex Benth. | Polemoniaceae | 8 |
| Gilia stellata | A.Heller | Polemoniaceae | 8 |
| Gilia transmontana | (H.Mason & A.D.Grant) A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Giliastrum acerosum | (A.Gray) Rydb. | Polemoniaceae | 8 |
| Glossopetalon spinescens | A.Gray | Crossosomataceae | 8 |
| Glyceria borealis | (Nash) Batch. | Poaceae | 8 |
| Glyceria elata | (Nash) M.E.Jones | Poaceae | 8 |
| Glyceria grandis | S.Watson | Poaceae | 8 |
| Glyceria striata | (Lam.) Hitchc. | Poaceae | 8 |
| Glycyrrhiza lepidota | Pursh | Fabaceae | 8 |
| Gnaphalium palustre | Nutt. | Asteraceae | 8 |
| Gomphrena caespitosa | Torr. | Amaranthaceae | 8 |
| Gomphrena sonorae | Torr. ex Emory | Amaranthaceae | 8 |
| Goodyera oblongifolia | Raf. | Orchidaceae | 8 |
| Goodyera repens | (L.) R.Br. | Orchidaceae | 8 |
| Gossypium thurberi | Tod. | Malvaceae | 8 |
| Gratiola neglecta | Torr. | Plantaginaceae | 8 |
| Grayia spinosa | (Hook.) Moq. | Chenopodiaceae | 8 |
| Grindelia ciliata | (Nutt.) Spreng. | Asteraceae | 8 |
| Grindelia hirsutula | Hook. & Arn. | Asteraceae | 8 |
| Grindelia squarrosa | (Pursh) Dunal | Asteraceae | 8 |
| Grusonia emoryi | (Engelm.) Pinkava | Cactaceae | 8 |
| Grusonia kunzei | (Rose) Pinkava | Cactaceae | 8 |
| Grusonia parishii | (Orcutt) Pinkava | Cactaceae | 8 |
| Guardiola platyphylla | A.Gray | Asteraceae | 8 |
| Guilleminea densa | (Humb. & Bonpl. ex Schult.) Moq. | Amaranthaceae | 8 |
| Gutierrezia microcephala | (DC.) A.Gray | Asteraceae | 8 |
| Gutierrezia sarothrae | (Pursh) Britton & Rusby | Asteraceae | 8 |
| Gutierrezia sphaerocephala | A.Gray | Asteraceae | 8 |
| Gymnocarpium dryopteris | (L.) Newman | Cystopteridaceae | 8 |
| Gymnosperma glutinosum | (Spreng.) Less. | Asteraceae | 8 |
| Habranthus longifolius | (Hemsl.) Flagg, G.Lom.Sm. & Meerow | Amaryllidaceae | 8 |
| Hackelia floribunda | (Lehm.) I.M.Johnst. | Boraginaceae | 8 |
| Halerpestes cymbalaria | Greene | Ranunculaceae | 8 |
| Haplophyton crooksii | (L.D.Benson) L.D.Benson | Apocynaceae | 8 |
| Harpagonella palmeri | A.Gray | Boraginaceae | 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 |
| Hedeoma dentata | Torr. | Lamiaceae | 8 |
| Hedeoma drummondii | Benth. | Lamiaceae | 8 |
| Hedeoma hyssopifolia | A.Gray | Lamiaceae | 8 |
| Hedeoma nana | (Torr.) Briq. | Lamiaceae | 8 |
| Hedeoma oblongifolia | (A.Gray) A.Heller | Lamiaceae | 8 |
| Hedeoma plicata | Torr. | Lamiaceae | 8 |
| Hedosyne ambrosiifolia | (A.Gray) Strother | Asteraceae | 8 |
| Hedysarum boreale | Nutt. | Fabaceae | 8 |
| Helenium autumnale | L. | Asteraceae | 8 |
| Helenium microcephalum | DC. | Asteraceae | 8 |
| Helenium thurberi | A.Gray | Asteraceae | 8 |
| Helianthella microcephala | A.Gray | Asteraceae | 8 |
| Helianthella quinquenervis | (Hook.) A.Gray | Asteraceae | 8 |
| Helianthella uniflora | Torr. & A.Gray | Asteraceae | 8 |
| Helianthus annuus | L. | Asteraceae | 8 |
| Helianthus ciliaris | DC. | Asteraceae | 8 |
| Helianthus deserticola | Heiser | Asteraceae | 8 |
| Helianthus niveus | (Benth.) Brandegee | Asteraceae | 8 |
| Helianthus nuttallii | Torr. & A.Gray | Asteraceae | 8 |
| Helianthus petiolaris | Nutt. | Asteraceae | 8 |
| Heliomeris longifolia | Cockerell | Asteraceae | 8 |
| Heliomeris multiflora | Nutt. | Asteraceae | 8 |
| Heliopsis parvifolia | A.Gray | Asteraceae | 8 |
| Heliotropium curassavicum | L. | Heliotropiaceae | 8 |
| Henrya insularis | Nees | Acanthaceae | 8 |
| Heracleum maximum | W.Bartram | Apiaceae | 8 |
| Herissantia crispa | (L.) Brizicky | Malvaceae | 8 |
| Herrickia glauca | (Nutt.) Brouillet | Asteraceae | 8 |
| Hesperidanthus linearifolius | (A.Gray) Rydb. | Brassicaceae | 8 |
| Hesperocallis undulata | A.Gray | Asparagaceae | 8 |
| Hesperochiron pumilus | (Griseb.) Porter | Hydrophyllaceae | 8 |
| Hesperocyparis arizonica | (Greene) Bartel | Cupressaceae | 8 |
| Hesperocyparis glabra | (Sudw.) Bartel | Cupressaceae | 8 |
| Hesperostipa comata | (Trin. & Rupr.) Barkworth | Poaceae | 8 |
| Hesperostipa neomexicana | (Thurb.) Barkworth | Poaceae | 8 |
| Heteranthera dubia | (Jacq.) MacMill. | Pontederiaceae | 8 |
| Heteranthera limosa | (Sw.) Willd. | Pontederiaceae | 8 |
| Heteropogon contortus | (L.) P.Beauv. ex Roem. & Schult. | Poaceae | 8 |
| Heteropogon melanocarpus | (Elliott) Benth. | Poaceae | 8 |
| Heterosperma pinnatum | Cav. | Asteraceae | 8 |
| Heterotheca fulcrata | (Greene) Shinners | Asteraceae | 8 |
| Heterotheca grandiflora | Nutt. | Asteraceae | 8 |
| Heterotheca polothrix | G.L.Nesom | Asteraceae | 8 |
| Heterotheca subaxillaris | (Lam.) Britton & Rusby | Asteraceae | 8 |
| Heterotheca viscida | (A.Gray) V.L.Harms | Asteraceae | 8 |
| Heterotheca zionensis | Semple | Asteraceae | 8 |
| Heuchera glomerulata | Rosend., Butters & Lakela | Saxifragaceae | 8 |
| Heuchera inconstans | R.A.Folk | Saxifragaceae | 8 |
| Heuchera novomexicana | Wheelock | 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 coulteri | Harv. ex A.Gray | Malvaceae | 8 |
| Hibiscus denudatus | Benth. | Malvaceae | 8 |
| Hieracium abscissum | Less. | Asteraceae | 8 |
| Hieracium fendleri | Sch.Bip. | Asteraceae | 8 |
| Hilaria belangeri | (Steud.) Nash | Poaceae | 8 |
| Hilaria jamesii | (Torr.) Benth. | Poaceae | 8 |
| Hilaria mutica | (Buckley) Benth. | Poaceae | 8 |
| Hippuris vulgaris | L. | Plantaginaceae | 8 |
| Hoffmannseggia drepanocarpa | A.Gray | Fabaceae | 8 |
| Hoffmannseggia glauca | (Ortega) Eifert | Fabaceae | 8 |
| Hoffmannseggia microphylla | Torr. | Fabaceae | 8 |
| Holodiscus discolor | (Pursh) Maxim. | Rosaceae | 8 |
| Hopia obtusa | (Kunth) Zuloaga & Morrone | Poaceae | 8 |
| Hordeum brachyantherum | Nevski | Poaceae | 8 |
| Hordeum jubatum | L. | Poaceae | 8 |
| Horsfordia alata | (S.Watson) A.Gray | Malvaceae | 8 |
| Horsfordia newberryi | (S.Watson) A.Gray | Malvaceae | 8 |
| Houstonia rubra | Cav. | Rubiaceae | 8 |
| Houstonia wrightii | A.Gray | Rubiaceae | 8 |
| Hulsea heterochroma | A.Gray | Asteraceae | 8 |
| Humulus neomexicanus | (A.Nelson & Cockerell) Rydb. | Cannabaceae | 8 |
| Hydrocotyle ranunculoides | L.f. | Araliaceae | 8 |
| Hydrocotyle verticillata | Thunb. | Araliaceae | 8 |
| Hydrophyllum occidentale | (S.Watson) A.Gray | Hydrophyllaceae | 8 |
| Hymenopappus filifolius | Hook. | Asteraceae | 8 |
| Hymenopappus mexicanus | A.Gray | Asteraceae | 8 |
| Hymenothrix dissecta | (A.Gray) B.G.Baldwin | Asteraceae | 8 |
| Hymenothrix wislizeni | A.Gray | Asteraceae | 8 |
| Hymenothrix wrightii | A.Gray | Asteraceae | 8 |
| Hymenoxys bigelovii | (A.Gray) K.F.Parker | Asteraceae | 8 |
| Hymenoxys brandegeei | (Porter ex A.Gray) K.F.Parker | Asteraceae | 8 |
| Hymenoxys cooperi | Cockerell | Asteraceae | 8 |
| Hymenoxys hoopesii | (A.Gray) Bierner | Asteraceae | 8 |
| Hymenoxys odorata | DC. | Asteraceae | 8 |
| Hymenoxys richardsonii | Cockerell | Asteraceae | 8 |
| Hymenoxys rusbyi | Cockerell | Asteraceae | 8 |
| Hypericum anagalloides | Cham. & Schltdl. | Hypericaceae | 8 |
| Hypericum scouleri | Hook. | Hypericaceae | 8 |
| Hypopitys monotropa | Crantz | Ericaceae | 8 |
| Ibervillea tenuisecta | (A.Gray) Small | Cucurbitaceae | 8 |
| Ipomoea aristolochiifolia | G.Don | Convolvulaceae | 8 |
| Ipomoea barbatisepala | A.Gray | Convolvulaceae | 8 |
| Ipomoea capillacea | (Kunth) G.Don | Convolvulaceae | 8 |
| Ipomoea cardiophylla | A.Gray | Convolvulaceae | 8 |
| Ipomoea costellata | Torr. | Convolvulaceae | 8 |
| Ipomoea cristulata | Hallier f. | Convolvulaceae | 8 |
| Ipomoea hederifolia | L. | Convolvulaceae | 8 |
| Ipomoea longifolia | Benth. | Convolvulaceae | 8 |
| Ipomoea plummerae | A.Gray | Convolvulaceae | 8 |
| Ipomoea pubescens | Lam. | Convolvulaceae | 8 |
| Ipomoea purpurea | (L.) Roth | Convolvulaceae | 8 |
| Ipomoea ternifolia | Cav. | Convolvulaceae | 8 |
| Ipomopsis aggregata | (Pursh) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis arizonica | (Greene) Wherry | Polemoniaceae | 8 |
| Ipomopsis congesta | (Hook.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis gunnisonii | (Torr. & A.Gray) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis laxiflora | (J.M.Coult.) 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 macrosiphon | (Kearney & Peebles) V.E.Grant & Wilken | Polemoniaceae | 8 |
| Ipomopsis multiflora | (Nutt.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis polycladon | (Torr.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis pumila | (Nutt.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis tenuifolia | (A.Gray) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis tenuituba | (Rydb.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis thurberi | (A.Gray) V.E.Grant | Polemoniaceae | 8 |
| Iresine heterophylla | Standl. | Amaranthaceae | 8 |
| Iris missouriensis | Nutt. | Iridaceae | 8 |
| Isocoma acradenia | (Greene) Greene | Asteraceae | 8 |
| Isocoma pluriflora | (Torr. & A.Gray) Greene | Asteraceae | 8 |
| Isocoma tenuisecta | Greene | Asteraceae | 8 |
| Isoetes bolanderi | Engelm. | Isoetaceae | 8 |
| Iva axillaris | Pursh | Asteraceae | 8 |
| Jacquemontia evolvuloides | Meisn. | Convolvulaceae | 8 |
| Jacquemontia pringlei | A.Gray | Convolvulaceae | 8 |
| Jaltomata procumbens | (Cav.) J.L.Gentry | Solanaceae | 8 |
| Jamesia americana | Torr. & A.Gray | Hydrangeaceae | 8 |
| Jatropha cardiophylla | (Torr.) Müll.Arg. | Euphorbiaceae | 8 |
| Jatropha cinerea | (Ortega) Müll.Arg. | Euphorbiaceae | 8 |
| Jatropha cuneata | Wiggins & Rollins | Euphorbiaceae | 8 |
| Jatropha macrorhiza | Benth. | Euphorbiaceae | 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 pusilla | (Torr. & A.Gray) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella racemosa | (S.Watson ex A.Gray) Brand | Boraginaceae | 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 biflorus | Elliott | Juncaceae | 8 |
| Juncus bufonius | L. | Juncaceae | 8 |
| Juncus dudleyi | Wiegand | Juncaceae | 8 |
| Juncus effusus | L. | Juncaceae | 8 |
| Juncus interior | Wiegand | Juncaceae | 8 |
| Juncus marginatus | Rostk. | Juncaceae | 8 |
| Juncus mertensianus | Bong. | Juncaceae | 8 |
| Juncus nodosus | L. | Juncaceae | 8 |
| Juncus occidentalis | (Coville) Wiegand | Juncaceae | 8 |
| Juncus tenuis | Willd. | Juncaceae | 8 |
| Juncus torreyi | Coville | Juncaceae | 8 |
| Juncus tweedyi | Rydb. | Juncaceae | 8 |
| Juncus xiphioides | E.Mey. | Juncaceae | 8 |
| Juniperus arizonica | (R.P.Adams) R.P.Adams | Cupressaceae | 8 |
| Juniperus californica | Carrière | Cupressaceae | 8 |
| Juniperus communis | L. | Cupressaceae | 8 |
| Juniperus deppeana | Steud. | Cupressaceae | 8 |
| Juniperus monosperma | (Engelm.) Sarg. | Cupressaceae | 8 |
| Juniperus osteosperma | (Torr.) Little | 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 |
| Kallstroemia californica | (S.Watson) Vail | Zygophyllaceae | 8 |
| Kallstroemia grandiflora | Torr. ex A.Gray | Zygophyllaceae | 8 |
| Kallstroemia parviflora | Norton | Zygophyllaceae | 8 |
| Keckiella antirrhinoides | (Benth.) Straw | Plantaginaceae | 8 |
| Kelloggia galioides | Torr. | Rubiaceae | 8 |
| Koeberlinia spinosa | Zucc. | Koeberliniaceae | 8 |
| Koeleria macrantha | (Ledeb.) Schult. | Poaceae | 8 |
| Koeleria spicata | (L.) Barberá, Quintanar, Soreng & P.M.Peterson | Poaceae | 8 |
| Krameria bicolor | S.Watson | Krameriaceae | 8 |
| Krameria erecta | Willd. | Krameriaceae | 8 |
| Krameria lanceolata | Torr. | Krameriaceae | 8 |
| Krascheninnikovia ceratoides | (L.) Gueldenst. | Chenopodiaceae | 8 |
| Krigia biflora | (Walter) S.F.Blake | Asteraceae | 8 |
| Lactuca canadensis | L. | Asteraceae | 8 |
| Lactuca graminifolia | Michx. | Asteraceae | 8 |
| Lactuca ludoviciana | (Nutt.) Riddell | Asteraceae | 8 |
| Lactuca oblongifolia | Nutt. | Asteraceae | 8 |
| Ladeania lanceolata | (Pursh) Reveal & A.N.Egan | Fabaceae | 8 |
| Laennecia coulteri | (A.Gray) G.L.Nesom | Asteraceae | 8 |
| Laennecia schiedeana | (Less.) G.L.Nesom | Asteraceae | 8 |
| Laennecia sophiifolia | (Kunth) G.L.Nesom | Asteraceae | 8 |
| Lagascea decipiens | Hemsl. | Asteraceae | 8 |
| Langloisia setosissima | (Torr. & A.Gray) Greene | Polemoniaceae | 8 |
| Lantana achyranthifolia | Desf. | Verbenaceae | 8 |
| Lappula occidentalis | (S.Watson) Greene | Boraginaceae | 8 |
| Larrea tridentata | (DC.) Coville | Zygophyllaceae | 8 |
| Lasianthaea podocephala | (A.Gray) K.M.Becker | Asteraceae | 8 |
| Lasthenia gracilis | (DC.) Greene | Asteraceae | 8 |
| Lathyrus brachycalyx | Rydb. | Fabaceae | 8 |
| Lathyrus eucosmus | Butters & H.St.John | Fabaceae | 8 |
| Lathyrus graminifolius | (S.Watson) T.G.White | Fabaceae | 8 |
| Lathyrus lanszwertii | Kellogg | Fabaceae | 8 |
| Layia glandulosa | (Hook.) Hook. & Arn. | Asteraceae | 8 |
| Leersia oryzoides | (L.) Sw. | Poaceae | 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 |
| Lemna trisulca | L. | Araceae | 8 |
| Lemna turionifera | Landolt | Araceae | 8 |
| Lepidium alyssoides | A.Gray | Brassicaceae | 8 |
| Lepidium densiflorum | Schrad. | Brassicaceae | 8 |
| Lepidium fremontii | S.Watson | Brassicaceae | 8 |
| Lepidium lasiocarpum | Nutt. | Brassicaceae | 8 |
| Lepidium montanum | Nutt. | Brassicaceae | 8 |
| Lepidium oblongum | Small | Brassicaceae | 8 |
| Lepidium thurberi | Wooton | Brassicaceae | 8 |
| Lepidium virginicum | L. | Brassicaceae | 8 |
| Leptochloa crinita | (Lag.) P.M.Peterson & N.Snow | Poaceae | 8 |
| Leptochloa nealleyi | Vasey | Poaceae | 8 |
| Leptochloa panicea | (Retz.) Ohwi | Poaceae | 8 |
| Leptosiphon chrysanthus | J.M.Porter & R.Patt. | Polemoniaceae | 8 |
| Leptosiphon floribundus | (A.Gray) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Leptosiphon nuttallii | (A.Gray) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Lessingia glandulifera | A.Gray | Asteraceae | 8 |
| Leucocrinum montanum | Nutt. ex A.Gray | Asparagaceae | 8 |
| Leucosyris carnosa | (A.Gray) Greene | Asteraceae | 8 |
| Lewisia brachycalyx | Engelm. ex A.Gray | Montiaceae | 8 |
| Lewisia nevadensis | (A.Gray) B.L.Rob. | Montiaceae | 8 |
| Lewisia pygmaea | (A.Gray) B.L.Rob. | Montiaceae | 8 |
| Lewisia rediviva | Pursh | Montiaceae | 8 |
| Leymus cinereus | (Scribn. & Merr.) Á.Löve | Poaceae | 8 |
| Leymus triticoides | (Buckley) Pilg. | Poaceae | 8 |
| Ligusticum porteri | J.M.Coult. & Rose | Apiaceae | 8 |
| Lilium parryi | S.Watson | Liliaceae | 8 |
| Limonium limbatum | Small | Plumbaginaceae | 8 |
| Limosella aquatica | L. | Plantaginaceae | 8 |
| Linanthus demissus | (A.Gray) Greene | Polemoniaceae | 8 |
| Linanthus dichotomus | Benth. | Polemoniaceae | 8 |
| Linanthus filiformis | (Parry ex A.Gray) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Linanthus jonesii | (A.Gray) Greene | Polemoniaceae | 8 |
| Linanthus pungens | (Torr.) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Linanthus watsonii | (A.Gray) Wherry | Polemoniaceae | 8 |
| Lindernia dubia | (L.) Pennell | Linderniaceae | 8 |
| Linnaea borealis | L. | Caprifoliaceae | 8 |
| Linum aristatum | Engelm. | Linaceae | 8 |
| Linum australe | A.Heller | Linaceae | 8 |
| Linum lewisii | Pursh | Linaceae | 8 |
| Linum neomexicanum | Greene | Linaceae | 8 |
| Linum pratense | (Norton) Small | Linaceae | 8 |
| Linum puberulum | (Engelm.) A.Heller | Linaceae | 8 |
| Linum subteres | (Trel.) H.J.P.Winkl. | Linaceae | 8 |
| Lithophragma tenellum | Nutt. | Saxifragaceae | 8 |
| Lithospermum cobrense | Greene | Boraginaceae | 8 |
| Lithospermum incisum | Lehm. | Boraginaceae | 8 |
| Lithospermum multiflorum | Torr. ex A.Gray | Boraginaceae | 8 |
| Lithospermum viride | Greene | Boraginaceae | 8 |
| Lobelia anatina | E.Wimm. | Campanulaceae | 8 |
| Lobelia cardinalis | L. | Campanulaceae | 8 |
| Lobelia fenestralis | Cav. | Campanulaceae | 8 |
| Lobelia laxiflora | Kunth | Campanulaceae | 8 |
| Loeflingia squarrosa | Nutt. | Caryophyllaceae | 8 |
| Loeselia glandulosa | (Cav.) G.Don | Polemoniaceae | 8 |
| Loeseliastrum schottii | (Torr.) Timbrook | Polemoniaceae | 8 |
| Logfia arizonica | (A.Gray) Holub | Asteraceae | 8 |
| Logfia depressa | (A.Gray) Holub | Asteraceae | 8 |
| Lomatium foeniculaceum | (Nutt.) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium mohavense | (J.M.Coult. & Rose) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium multifidum | (Nutt.) R.P.McNeill & Darrach | Apiaceae | 8 |
| Lomatium nevadense | (S.Watson) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium orientale | J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium parryi | (S.Watson) J.F.Macbr. | Apiaceae | 8 |
| Lonicera albiflora | Torr. & A.Gray | Caprifoliaceae | 8 |
| Lonicera arizonica | Rehder | Caprifoliaceae | 8 |
| Lonicera interrupta | Benth. | Caprifoliaceae | 8 |
| Lonicera involucrata | (Richardson) Banks ex Spreng. | Caprifoliaceae | 8 |
| Lonicera utahensis | S.Watson | Caprifoliaceae | 8 |
| Lophocereus schottii | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Lorandersonia baileyi | (Wooton & Standl.) Urbatsch, R.P.Roberts & Neubig | Asteraceae | 8 |
| Ludwigia erecta | (L.) H.Hara | Onagraceae | 8 |
| Ludwigia palustris | (L.) Elliott | Onagraceae | 8 |
| Ludwigia peploides | (Kunth) P.H.Raven | Onagraceae | 8 |
| Ludwigia repens | J.R.Forst. | Onagraceae | 8 |
| Lupinus argenteus | Pursh | Fabaceae | 8 |
| Lupinus arizonicus | (S.Watson) S.Watson | Fabaceae | 8 |
| Lupinus barbiger | S.Watson | Fabaceae | 8 |
| Lupinus bicolor | Lindl. | Fabaceae | 8 |
| Lupinus brevicaulis | S.Watson | Fabaceae | 8 |
| Lupinus breweri | A.Gray | Fabaceae | 8 |
| Lupinus caudatus | Kellogg | Fabaceae | 8 |
| Lupinus concinnus | J.Agardh | Fabaceae | 8 |
| Lupinus flavoculatus | A.Heller | Fabaceae | 8 |
| Lupinus hillii | Greene | Fabaceae | 8 |
| Lupinus huachucanus | M.E.Jones | Fabaceae | 8 |
| Lupinus kingii | S.Watson | Fabaceae | 8 |
| Lupinus latifolius | Lindl. ex J.Agardh | Fabaceae | 8 |
| Lupinus microcarpus | Sims | Fabaceae | 8 |
| Lupinus neomexicanus | Greene | Fabaceae | 8 |
| Lupinus pusillus | Pursh | Fabaceae | 8 |
| Lupinus shockleyi | S.Watson | Fabaceae | 8 |
| Lupinus sparsiflorus | Benth. | Fabaceae | 8 |
| Luzula comosa | E.Mey. | Juncaceae | 8 |
| Luzula parviflora | (Ehrh.) Desv. | Juncaceae | 8 |
| Luzula spicata | (L.) DC. | Juncaceae | 8 |
| Lycium andersonii | A.Gray | Solanaceae | 8 |
| Lycium berlandieri | Dunal | Solanaceae | 8 |
| Lycium californicum | Nutt. ex A.Gray | Solanaceae | 8 |
| Lycium cooperi | A.Gray | 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 |
| Lycopus americanus | Muhl. ex W.P.C.Barton | Lamiaceae | 8 |
| Lycopus asper | Greene | Lamiaceae | 8 |
| Lygodesmia juncea | (Pursh) Sweet | Asteraceae | 8 |
| Lyrocarpa coulteri | Hook. & Harv. | Brassicaceae | 8 |
| Lysimachia hybrida | Michx. | Primulaceae | 8 |
| Lysimachia minima | (L.) U.Manns & Anderb. | Primulaceae | 8 |
| Lythrum californicum | Torr. & A.Gray | Lythraceae | 8 |
| Mabrya acerifolia | (Pennell) Elisens | Plantaginaceae | 8 |
| Machaeranthera tagetina | Greene | Asteraceae | 8 |
| Machaeranthera tanacetifolia | (Kunth) Nees | Asteraceae | 8 |
| Macroptilium gibbosifolium | (Ortega) A.Delgado | Fabaceae | 8 |
| Madia glomerata | Hook. | Asteraceae | 8 |
| Maianthemum racemosum | (L.) Link | Asparagaceae | 8 |
| Maianthemum stellatum | (L.) Link | Asparagaceae | 8 |
| Malacothamnus orbiculatus | (Greene) Greene | Malvaceae | 8 |
| Malacothrix coulteri | Harv. & A.Gray | Asteraceae | 8 |
| Malacothrix fendleri | A.Gray | Asteraceae | 8 |
| Malacothrix glabrata | (A.Gray ex D.C.Eaton) A.Gray | Asteraceae | 8 |
| Malacothrix sonchoides | (Nutt.) Torr. & A.Gray | Asteraceae | 8 |
| Malacothrix stebbinsii | W.S.Davis & P.H.Raven | Asteraceae | 8 |
| Malacothrix torreyi | A.Gray | Asteraceae | 8 |
| Malaxis brachystachys | (Rchb.f.) Kuntze | Orchidaceae | 8 |
| Malaxis macrostachya | (Lex.) Kuntze | Orchidaceae | 8 |
| Malvella lepidota | (A.Gray) Fryxell | Malvaceae | 8 |
| Malvella leprosa | (Ortega) Krapov. | Malvaceae | 8 |
| Malvella sagittifolia | (A.Gray) Fryxell | Malvaceae | 8 |
| Mammillaria heyderi | Muehlenpf. | Cactaceae | 8 |
| Mandevilla foliosa | (Müll.Arg.) Hemsl. | Apocynaceae | 8 |
| Manihot angustiloba | (Torr.) Müll.Arg. | Euphorbiaceae | 8 |
| Marah gilensis | (Greene) Greene | Cucurbitaceae | 8 |
| Marina calycosa | (A.Gray) Barneby | Fabaceae | 8 |
| Marina filiciformis | (B.L.Rob. & Greenm.) Piñeros-U. & F.González | Fabaceae | 8 |
| Marina parryi | (Torr. & A.Gray) Barneby | Fabaceae | 8 |
| Marsilea vestita | Hook. & Grev. | Marsileaceae | 8 |
| Matricaria discoidea | DC. | Asteraceae | 8 |
| Maurandella antirrhiniflora | (Humb. & Bonpl. ex Willd.) Rothm. | Plantaginaceae | 8 |
| Melampodium leucanthum | Torr. & A.Gray | Asteraceae | 8 |
| Melampodium strigosum | Stuessy | Asteraceae | 8 |
| Melica frutescens | Scribn. | Poaceae | 8 |
| Melica imperfecta | Trin. | Poaceae | 8 |
| Melica nitens | (Scribn.) Nutt. ex Piper | Poaceae | 8 |
| Menodora scabra | Engelm. ex A.Gray | Oleaceae | 8 |
| Mentha canadensis | L. | Lamiaceae | 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 involucrata | S.Watson | Loasaceae | 8 |
| Mentzelia laevicaulis | (Douglas ex Hook.) Torr. & A.Gray | Loasaceae | 8 |
| Mentzelia longiloba | J.Darl. | Loasaceae | 8 |
| Mentzelia montana | (Davidson) Davidson | Loasaceae | 8 |
| Mentzelia oligosperma | Nutt. ex Sims | Loasaceae | 8 |
| Mentzelia procera | (Wooton & Standl.) J.J.Schenk & L.Hufford | Loasaceae | 8 |
| Mentzelia puberula | J.Darl. | Loasaceae | 8 |
| Mentzelia rusbyi | Wooton | Loasaceae | 8 |
| Mentzelia tricuspis | A.Gray | Loasaceae | 8 |
| Mentzelia veatchiana | Kellogg | Loasaceae | 8 |
| Menyanthes trifoliata | L. | Menyanthaceae | 8 |
| Mertensia arizonica | Greene | Boraginaceae | 8 |
| Mertensia ciliata | (E.James ex Torr.) G.Don | Boraginaceae | 8 |
| Mertensia franciscana | A.Heller | Boraginaceae | 8 |
| Mertensia macdougalii | A.Heller | Boraginaceae | 8 |
| Metastelma arizonicum | A.Gray | Apocynaceae | 8 |
| Micranthes eriophora | (S.Watson) Small | Saxifragaceae | 8 |
| Micranthes odontoloma | A.Heller | Saxifragaceae | 8 |
| Micranthes rhomboidea | Small | Saxifragaceae | 8 |
| Microsteris gracilis | (Hook.) Greene | Polemoniaceae | 8 |
| Milla biflora | Cav. | Asparagaceae | 8 |
| Mimetanthe pilosa | (Benth.) Greene | Phrymaceae | 8 |
| Mimosa aculeaticarpa | Ortega | Fabaceae | 8 |
| Mimosa biuncifera | Benth. | Fabaceae | 8 |
| Mimosa distachya | Cav. | Fabaceae | 8 |
| Mimosa dysocarpa | Benth. | Fabaceae | 8 |
| Mimosa grahamii | A.Gray | Fabaceae | 8 |
| Mirabilis albida | (Walter) Heimerl | Nyctaginaceae | 8 |
| Mirabilis coccinea | (Torr.) Benth. & Hook.f. | Nyctaginaceae | 8 |
| Mirabilis comata | (Small) Standl. | Nyctaginaceae | 8 |
| Mirabilis glabra | (S.Watson) Standl. | Nyctaginaceae | 8 |
| Mirabilis laevis | (Benth.) Curran | Nyctaginaceae | 8 |
| Mirabilis linearis | (Pursh) Heimerl | Nyctaginaceae | 8 |
| Mirabilis longiflora | L. | Nyctaginaceae | 8 |
| Mirabilis melanotricha | (Standl.) Spellenb. | Nyctaginaceae | 8 |
| Mirabilis multiflora | (Torr.) A.Gray | Nyctaginaceae | 8 |
| Mirabilis oxybaphoides | (A.Gray) A.Gray | Nyctaginaceae | 8 |
| Mirabilis tenuiloba | S.Watson | Nyctaginaceae | 8 |
| Mohavea breviflora | Coville | Plantaginaceae | 8 |
| Mohavea confertiflora | (Benth.) Jeps. | Plantaginaceae | 8 |
| Mollugo verticillata | L. | Molluginaceae | 8 |
| Monarda citriodora | Cerv. ex Lag. | Lamiaceae | 8 |
| Monarda fistulosa | L. | Lamiaceae | 8 |
| Monarda pectinata | Nutt. | Lamiaceae | 8 |
| Monardella breweri | A.Gray | Lamiaceae | 8 |
| Monardella exilis | (A.Gray) Greene | Lamiaceae | 8 |
| Monardella odoratissima | Benth. | Lamiaceae | 8 |
| Moneses uniflora | (L.) A.Gray | Ericaceae | 8 |
| Monnina wrightii | A.Gray | Polygalaceae | 8 |
| Monoptilon bellioides | H.M.Hall | Asteraceae | 8 |
| Montia chamissoi | (Ledeb. ex Spreng.) Greene | Montiaceae | 8 |
| Montia linearis | (Douglas ex Hook.) Greene | Montiaceae | 8 |
| Morisonia atamisquea | (Kuntze) Christenh. & Byng | Capparaceae | 8 |
| Mortonia scabrella | A.Gray | Celastraceae | 8 |
| Mortonia utahensis | (Coville) A.Nelson | Celastraceae | 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 depauperata | Scribn. | Poaceae | 8 |
| Muhlenbergia emersleyi | Vasey | Poaceae | 8 |
| Muhlenbergia longiligula | Hitchc. | Poaceae | 8 |
| Muhlenbergia mexicana | (L.) Trin. | Poaceae | 8 |
| Muhlenbergia microsperma | Trin. | Poaceae | 8 |
| Muhlenbergia minutissima | (Steud.) Swallen | Poaceae | 8 |
| Muhlenbergia montana | (Nutt.) Hitchc. | Poaceae | 8 |
| Muhlenbergia multiflora | Columbus | Poaceae | 8 |
| Muhlenbergia paniculata | (Nutt.) P.M.Peterson | Poaceae | 8 |
| Muhlenbergia peruviana | (P.Beauv.) Steud. | Poaceae | 8 |
| Muhlenbergia porteri | Scribn. | Poaceae | 8 |
| Muhlenbergia racemosa | (Michx.) Britton, Sterns & Poggenb. | Poaceae | 8 |
| Muhlenbergia richardsonis | (Trin.) Rydb. | Poaceae | 8 |
| Muhlenbergia rigens | (Benth.) Hitchc. | Poaceae | 8 |
| Muhlenbergia rigida | (Kunth) Kunth | Poaceae | 8 |
| Muhlenbergia schreberi | J.F.Gmel. | Poaceae | 8 |
| Muhlenbergia setifolia | Vasey | Poaceae | 8 |
| Muhlenbergia sinuosa | Swallen | Poaceae | 8 |
| Muhlenbergia sylvatica | Torr. | 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 |
| Munroa squarrosa | (Nutt.) Torr. | Poaceae | 8 |
| Myosotis verna | Nutt. | Boraginaceae | 8 |
| Myriophyllum quitense | Kunth | Haloragaceae | 8 |
| Myriophyllum sibiricum | Kom. | Haloragaceae | 8 |
| Myriophyllum verticillatum | L. | Haloragaceae | 8 |
| Myriopteris alabamensis | (Buckley) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris aurea | (Poir.) 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 parryi | (D.C.Eaton) Grusz & Windham | Pteridaceae | 8 |
| Myriopteris rufa | Fée | Pteridaceae | 8 |
| Myriopteris tomentosa | (Link) Fée | 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 |
| 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 pusilla | Lemmon ex A.Gray | Namaceae | 8 |
| Nama rothrockii | A.Gray | Namaceae | 8 |
| Nama stenocarpa | A.Gray | Namaceae | 8 |
| Nassella viridula | (Trin.) Barkworth | Poaceae | 8 |
| Navarretia breweri | (A.Gray) Greene | Polemoniaceae | 8 |
| Navarretia intertexta | Hook. | Polemoniaceae | 8 |
| Neltuma odorata | (Torr. & Frém.) C.E.Hughes & G.P.Lewis | Fabaceae | 8 |
| Neltuma velutina | (Wooton) Britton & Rose | Fabaceae | 8 |
| Nemacaulis denudata | Nutt. | Polygonaceae | 8 |
| Nemacladus glanduliferus | Jeps. | Campanulaceae | 8 |
| Nemacladus orientalis | (McVaugh) Morin | Campanulaceae | 8 |
| Nemacladus rubescens | Greene | Campanulaceae | 8 |
| Nemacladus sigmoideus | G.T.Robbins | Campanulaceae | 8 |
| Nemastylis tenuis | (Herb.) Benth. & Hook.f. ex S.Watson | Iridaceae | 8 |
| Neogaerrhinum filipes | (A.Gray) Rothm. | Plantaginaceae | 8 |
| Neokochia americana | (S.Watson) G.L.Chu & S.C.Sand. | Chenopodiaceae | 8 |
| Neottia convallarioides | (Sw.) Rich. | Orchidaceae | 8 |
| Nephroia diversifolia | (DC.) L.Lian & Wei Wang | Menispermaceae | 8 |
| Nephrolepis exaltata | (L.) Schott | Nephrolepidaceae | 8 |
| Nicotiana attenuata | Torr. ex S.Watson | Solanaceae | 8 |
| Nicotiana clevelandii | A.Gray | Solanaceae | 8 |
| Nicotiana obtusifolia | M.Martens & Galeotti | Solanaceae | 8 |
| Nicotiana quadrivalvis | Pursh | Solanaceae | 8 |
| Nissolia platycalyx | S.Watson | Fabaceae | 8 |
| Nissolia schottii | A.Gray | Fabaceae | 8 |
| Noccaea fendleri | (A.Gray) Holub | Brassicaceae | 8 |
| Nolina bigelovii | (Torr.) S.Watson | Asparagaceae | 8 |
| Nolina microcarpa | S.Watson | Asparagaceae | 8 |
| Notholaena aschenborniana | Klotzsch | Pteridaceae | 8 |
| Notholaena lemmonii | D.C.Eaton | Pteridaceae | 8 |
| Nothoscordum bivalve | (L.) Britton | Amaryllidaceae | 8 |
| Nuphar polysepala | Engelm. | Nymphaeaceae | 8 |
| Nuttallanthus texanus | (Scheele) D.A.Sutton | Plantaginaceae | 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 coronopifolia | Torr. & A.Gray | Onagraceae | 8 |
| Oenothera curtiflora | W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera deltoides | Torr. & Frém. | Onagraceae | 8 |
| Oenothera elata | Kunth | Onagraceae | 8 |
| Oenothera flava | (A.Nelson) Garrett | Onagraceae | 8 |
| Oenothera hartwegii | Benth. | Onagraceae | 8 |
| Oenothera lavandulifolia | Torr. & A.Gray | 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 serrulata | Nutt. | Onagraceae | 8 |
| Oenothera suffrutescens | (Ser.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera toumeyi | (Small) Tidestr. | Onagraceae | 8 |
| Oenothera villosa | Thunb. | Onagraceae | 8 |
| Oligomeris linifolia | (Vahl ex Hornem.) J.F.Macbr. | Resedaceae | 8 |
| Olneya tesota | A.Gray | Fabaceae | 8 |
| Ophioglossum engelmannii | Prantl | Ophioglossaceae | 8 |
| Ophioglossum polyphyllum | A.Braun ex Seub. | Ophioglossaceae | 8 |
| Ophioglossum vulgatum | L. | Ophioglossaceae | 8 |
| Opuntia aurea | E.M.Baxter | Cactaceae | 8 |
| Opuntia basilaris | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Opuntia chlorotica | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Opuntia curvispina | Griffiths | Cactaceae | 8 |
| Opuntia engelmannii | Salm-Dyck ex Engelm. | Cactaceae | 8 |
| Opuntia fragilis | (Nutt.) Haw. | Cactaceae | 8 |
| Opuntia gosseliniana | F.A.C.Weber | Cactaceae | 8 |
| Opuntia macrocentra | Engelm. | Cactaceae | 8 |
| Opuntia macrorhiza | Engelm. | Cactaceae | 8 |
| Opuntia orbiculata | Salm-Dyck ex Pfeiff. | Cactaceae | 8 |
| Opuntia phaeacantha | Engelm. | Cactaceae | 8 |
| Opuntia pinkavae | B.D.Parfitt | Cactaceae | 8 |
| Opuntia polyacantha | Haw. | Cactaceae | 8 |
| Opuntia pottsii | Salm-Dyck | Cactaceae | 8 |
| Oreocarya confertiflora | Greene | Boraginaceae | 8 |
| Oreocarya flava | A.Nelson | Boraginaceae | 8 |
| Oreocarya flavoculata | A.Nelson | Boraginaceae | 8 |
| Oreocarya fulvocanescens | (S.Watson) Greene | Boraginaceae | 8 |
| Oreocarya humilis | (A.Gray) Greene | Boraginaceae | 8 |
| Oreocarya setosissima | (A.Gray) Greene | Boraginaceae | 8 |
| Oreocarya suffruticosa | (Torr.) Greene | Boraginaceae | 8 |
| Oreochrysum parryi | Rydb. | Asteraceae | 8 |
| Orobanche cooperi | (A.Gray) A.Heller | Orobanchaceae | 8 |
| Orobanche corymbosa | (Rydb.) Ferris | Orobanchaceae | 8 |
| Orobanche fasciculata | Nutt. | Orobanchaceae | 8 |
| Orobanche uniflora | L. | Orobanchaceae | 8 |
| Orthilia secunda | (L.) House | Ericaceae | 8 |
| Orthocarpus luteus | Nutt. | Orobanchaceae | 8 |
| Orthocarpus purpureoalbus | A.Gray ex S.Watson | Orobanchaceae | 8 |
| Osmorhiza berteroi | DC. | Apiaceae | 8 |
| Osmorhiza brachypoda | Torr. ex Durand | Apiaceae | 8 |
| Osmorhiza depauperata | Phil. | Apiaceae | 8 |
| Ostrya knowltonii | Coville | Betulaceae | 8 |
| Oxalis caerulea | (Small) R.Knuth | Oxalidaceae | 8 |
| Oxalis californica | (Abrams) R.Knuth | Oxalidaceae | 8 |
| Oxalis decaphylla | Kunth | Oxalidaceae | 8 |
| Oxalis dillenii | Jacq. | Oxalidaceae | 8 |
| Oxalis latifolia | Kunth | Oxalidaceae | 8 |
| Oxalis pilosa | Nutt. | Oxalidaceae | 8 |
| Oxybaphus nyctagineus | (Michx.) Sweet | Nyctaginaceae | 8 |
| Oxypolis fendleri | (A.Gray) A.Heller | Apiaceae | 8 |
| Oxyria digyna | (L.) Hill | Polygonaceae | 8 |
| Oxytheca perfoliata | Torr. & A.Gray | Polygonaceae | 8 |
| Oxytropis lambertii | Pursh | Fabaceae | 8 |
| Oxytropis oreophila | A.Gray | Fabaceae | 8 |
| Packera cana | (Hook.) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera neomexicana | (A.Gray) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Palafoxia arida | B.L.Turner & M.I.Morris | Asteraceae | 8 |
| Panicum capillare | L. | Poaceae | 8 |
| Panicum dichotomiflorum | Michx. | Poaceae | 8 |
| Panicum hallii | Vasey | Poaceae | 8 |
| Panicum hirticaule | J.Presl | Poaceae | 8 |
| Panicum virgatum | L. | Poaceae | 8 |
| Pappophorum mucronulatum | Nees | Poaceae | 8 |
| Pappostipa speciosa | (Trin. & Rupr.) Romasch. | Poaceae | 8 |
| Parietaria hespera | Hinton | Urticaceae | 8 |
| Parietaria pensylvanica | Muhl. ex Willd. | Urticaceae | 8 |
| Parkinsonia florida | (Benth. ex A.Gray) S.Watson | Fabaceae | 8 |
| Parkinsonia microphylla | Torr. | Fabaceae | 8 |
| Parnassia palustris | L. | Celastraceae | 8 |
| Parnassia parviflora | DC. | Celastraceae | 8 |
| Parryella filifolia | Torr. & A.Gray | Fabaceae | 8 |
| Parthenium confertum | A.Gray | Asteraceae | 8 |
| Parthenium incanum | Kunth | Asteraceae | 8 |
| Parthenocissus quinquefolia | (L.) Planch. | Vitaceae | 8 |
| Paspalum distichum | L. | Poaceae | 8 |
| Paspalum setaceum | Michx. | Poaceae | 8 |
| Passiflora arida | (Mast. & Rose) Killip | Passifloraceae | 8 |
| Passiflora arizonica | (Killip) D.H.Goldman | Passifloraceae | 8 |
| Passiflora bryonioides | Kunth | Passifloraceae | 8 |
| Passiflora mexicana | Juss. | Passifloraceae | 8 |
| Paxistima myrsinites | (Pursh) Raf. | Celastraceae | 8 |
| Pectis angustifolia | Torr. | Asteraceae | 8 |
| Pectis cylindrica | Rydb. | Asteraceae | 8 |
| Pectis filipes | Harv. & Gray | 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 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 centranthera | A.Gray | Orobanchaceae | 8 |
| Pedicularis groenlandica | Retz. | Orobanchaceae | 8 |
| Pedicularis parryi | A.Gray | Orobanchaceae | 8 |
| Pedicularis procera | A.Gray | Orobanchaceae | 8 |
| Pedicularis racemosa | Douglas ex Benth. | Orobanchaceae | 8 |
| Pediocactus bradyi | L.D.Benson | Cactaceae | 8 |
| Pediocactus sileri | (Engelm. ex J.M.Coult.) L.D.Benson | Cactaceae | 8 |
| Pediocactus simpsonii | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Pediomelum castoreum | (S.Watson) Rydb. | Fabaceae | 8 |
| Pediomelum esculentum | (Pursh) Rydb. | Fabaceae | 8 |
| Pediomelum megalanthum | (Wooton & Standl.) Rydb. | Fabaceae | 8 |
| Pediomelum tenuiflorum | (Pursh) A.N.Egan | Fabaceae | 8 |
| Pelazoneuron puberulum | (Baker) A.R.Sm. & S.E.Fawc. | Thelypteridaceae | 8 |
| Pelecyphora alversonii | (J.M.Coult.) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pelecyphora missouriensis | (Sweet) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pelecyphora vivipara | (Nutt.) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pellaea atropurpurea | (L.) Link | Pteridaceae | 8 |
| Pellaea glabella | Mett. | Pteridaceae | 8 |
| Pellaea intermedia | Mett. | Pteridaceae | 8 |
| Pellaea mucronata | D.C.Eaton | 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 albomarginatus | M.E.Jones | Plantaginaceae | 8 |
| Penstemon ambiguus | Torr. | Plantaginaceae | 8 |
| Penstemon angustifolius | Nutt. ex Pursh | Plantaginaceae | 8 |
| Penstemon barbatus | (Cav.) Roth | Plantaginaceae | 8 |
| Penstemon bicolor | (Brandegee) Clokey & D.D.Keck | Plantaginaceae | 8 |
| Penstemon breviculus | (D.D.Keck) G.T.Nisbet & R.C.Jacks. | Plantaginaceae | 8 |
| Penstemon caespitosus | Nutt. ex A.Gray | Plantaginaceae | 8 |
| Penstemon clutei | A.Nelson | Plantaginaceae | 8 |
| Penstemon comarrhenus | A.Gray | Plantaginaceae | 8 |
| Penstemon confusus | M.E.Jones | Plantaginaceae | 8 |
| Penstemon dasyphyllus | A.Gray | Plantaginaceae | 8 |
| Penstemon eatonii | A.Gray | Plantaginaceae | 8 |
| Penstemon fendleri | Torr. & A.Gray | Plantaginaceae | 8 |
| Penstemon laevis | Pennell | Plantaginaceae | 8 |
| Penstemon lanceolatus | Benth. | Plantaginaceae | 8 |
| Penstemon leonardii | Rydb. | Plantaginaceae | 8 |
| Penstemon linarioides | A.Gray | Plantaginaceae | 8 |
| Penstemon oliganthus | Wooton & Standl. | Plantaginaceae | 8 |
| Penstemon ophianthus | Pennell | Plantaginaceae | 8 |
| Penstemon pachyphyllus | A.Gray ex Rydb. | Plantaginaceae | 8 |
| Penstemon palmeri | A.Gray | Plantaginaceae | 8 |
| Penstemon parryi | A.Gray | Plantaginaceae | 8 |
| Penstemon petiolatus | Brandegee | Plantaginaceae | 8 |
| Penstemon pinifolius | Greene | Plantaginaceae | 8 |
| Penstemon pseudoputus | (Crosswh.) N.H.Holmgren | Plantaginaceae | 8 |
| Penstemon pseudospectabilis | M.E.Jones | Plantaginaceae | 8 |
| Penstemon rostriflorus | Kellogg | Plantaginaceae | 8 |
| Penstemon rydbergii | A.Nelson | Plantaginaceae | 8 |
| Penstemon strictus | Benth. | Plantaginaceae | 8 |
| Penstemon subulatus | M.E.Jones | Plantaginaceae | 8 |
| Penstemon superbus | A.Nelson | Plantaginaceae | 8 |
| Penstemon thompsoniae | (A.Gray) Rydb. | Plantaginaceae | 8 |
| Penstemon thurberi | Torr. | Plantaginaceae | 8 |
| Penstemon utahensis | Eastw. | Plantaginaceae | 8 |
| Penstemon virgatus | A.Gray | Plantaginaceae | 8 |
| Penstemon watsonii | A.Gray | Plantaginaceae | 8 |
| Penstemon whippleanus | A.Gray | Plantaginaceae | 8 |
| Pericome caudata | A.Gray | Asteraceae | 8 |
| Perityle congesta | (M.E.Jones) Shinners | Asteraceae | 8 |
| Perityle emoryi | Torr. | Asteraceae | 8 |
| Perityle gilensis | (M.E.Jones) J.F.Macbr. | Asteraceae | 8 |
| Perityle lemmonii | (A.Gray) J.F.Macbr. | Asteraceae | 8 |
| Perityle microglossa | Benth. | Asteraceae | 8 |
| Perityle tenella | J.F.Macbr. | Asteraceae | 8 |
| Persicaria amphibia | (L.) Delarbre | Polygonaceae | 8 |
| Persicaria hydropiperoides | (Michx.) Small | Polygonaceae | 8 |
| Persicaria lapathifolia | (L.) Delarbre | Polygonaceae | 8 |
| Persicaria pensylvanica | (L.) M.Gómez | Polygonaceae | 8 |
| Persicaria punctata | Small | Polygonaceae | 8 |
| Persicaria vivipara | (L.) Ronse Decr. | Polygonaceae | 8 |
| Petalonyx nitidus | S.Watson | Loasaceae | 8 |
| Petalonyx thurberi | A.Gray | Loasaceae | 8 |
| Petradoria pumila | (Nutt.) Greene | Asteraceae | 8 |
| Petrophytum caespitosum | (Nutt.) Rydb. | Rosaceae | 8 |
| Peucephyllum schottii | A.Gray | Asteraceae | 8 |
| Phacelia affinis | A.Gray | Hydrophyllaceae | 8 |
| Phacelia alba | Rydb. | Hydrophyllaceae | 8 |
| Phacelia arizonica | A.Gray | Hydrophyllaceae | 8 |
| Phacelia bombycina | Wooton & Standl. | Hydrophyllaceae | 8 |
| Phacelia campanularia | A.Gray | Hydrophyllaceae | 8 |
| Phacelia corrugata | A.Nelson | Hydrophyllaceae | 8 |
| Phacelia crenulata | Torr. ex S.Watson | Hydrophyllaceae | 8 |
| Phacelia cryptantha | Greene | Hydrophyllaceae | 8 |
| Phacelia distans | Benth. | Hydrophyllaceae | 8 |
| Phacelia egena | (Brand) Greene ex J.T.Howell | Hydrophyllaceae | 8 |
| Phacelia fremontii | Torr. | Hydrophyllaceae | 8 |
| Phacelia heterophylla | Pursh | Hydrophyllaceae | 8 |
| Phacelia integrifolia | Torr. | Hydrophyllaceae | 8 |
| Phacelia ivesiana | Torr. | Hydrophyllaceae | 8 |
| Phacelia neglecta | M.E.Jones | Hydrophyllaceae | 8 |
| Phacelia palmeri | Torr. | Hydrophyllaceae | 8 |
| Phacelia parryi | Torr. | Hydrophyllaceae | 8 |
| Phacelia pedicellata | A.Gray | Hydrophyllaceae | 8 |
| Phacelia pulchella | A.Gray | Hydrophyllaceae | 8 |
| Phacelia ramosissima | Douglas ex Lehm. | Hydrophyllaceae | 8 |
| Phacelia rotundifolia | Torr. ex S.Watson | Hydrophyllaceae | 8 |
| Phacelia rupestris | Greene | Hydrophyllaceae | 8 |
| Phacelia saxicola | A.Gray | Hydrophyllaceae | 8 |
| Phacelia sericea | (Graham) A.Gray | Hydrophyllaceae | 8 |
| Phacelia tanacetifolia | Benth. | Hydrophyllaceae | 8 |
| Phacelia vallis-mortae | J.W.Voss | Hydrophyllaceae | 8 |
| Phalaris arundinacea | L. | Poaceae | 8 |
| Phalaris caroliniana | Walter | Poaceae | 8 |
| Phaseolus angustissimus | A.Gray | Fabaceae | 8 |
| Phaseolus filiformis | Benth. | Fabaceae | 8 |
| Phaseolus grayanus | Wooton & Standl. | Fabaceae | 8 |
| Phaseolus parvulus | Greene | Fabaceae | 8 |
| Phemeranthus brevicaulis | (S.Watson) Kiger | Montiaceae | 8 |
| Phemeranthus parviflorus | (Nutt.) Kiger | Montiaceae | 8 |
| Philadelphus microphyllus | A.Gray | Hydrangeaceae | 8 |
| Phleum alpinum | L. | Poaceae | 8 |
| Phlox amabilis | Brand | Polemoniaceae | 8 |
| Phlox austromontana | Coville | Polemoniaceae | 8 |
| Phlox griseola | Wherry | Polemoniaceae | 8 |
| Phlox hoodii | Richardson | Polemoniaceae | 8 |
| Phlox longifolia | Nutt. | Polemoniaceae | 8 |
| Phlox nana | Nutt. | Polemoniaceae | 8 |
| Phlox tenuifolia | E.E.Nelson | Polemoniaceae | 8 |
| Phlox woodhousei | (A.Gray) E.E.Nelson | Polemoniaceae | 8 |
| Pholisma sonorae | (Torr.) Yatsk. | Lennoaceae | 8 |
| Pholistoma auritum | (Lindl.) Lilja | Hydrophyllaceae | 8 |
| Pholistoma membranaceum | (Benth.) Constance | Hydrophyllaceae | 8 |
| Phoradendron californicum | Nutt. | Santalaceae | 8 |
| Phoradendron capitellatum | Torr. ex Trel. | Santalaceae | 8 |
| Phoradendron coryae | Trel. | Santalaceae | 8 |
| Phoradendron juniperinum | Engelm. ex A.Gray | Santalaceae | 8 |
| Phoradendron macrophyllum | (Engelm.) Cockerell | Santalaceae | 8 |
| Phoradendron pauciflorum | Torr. | 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 polygonoides | Nutt. ex Spreng. | Phyllanthaceae | 8 |
| Phyllanthus warnockii | G.L.Webster | Phyllanthaceae | 8 |
| Phyllodoce empetriformis | (Sm.) D.Don | Ericaceae | 8 |
| Physalis acutifolia | (Miers) Sandwith | Solanaceae | 8 |
| Physalis angulata | L. | Solanaceae | 8 |
| Physalis crassifolia | Benth. | Solanaceae | 8 |
| Physalis fendleri | A.Gray | Solanaceae | 8 |
| Physalis hederifolia | A.Gray | Solanaceae | 8 |
| Physalis longifolia | Nutt. | Solanaceae | 8 |
| Physalis neomexicana | Rydb. | Solanaceae | 8 |
| Physalis pubescens | L. | Solanaceae | 8 |
| Physalis solanacea | (Schltdl.) Axelius | Solanaceae | 8 |
| Physaria acutifolia | Rydb. | Brassicaceae | 8 |
| Physaria chambersii | Rollins | Brassicaceae | 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 ludoviciana | (Nutt.) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria montana | (A.Gray) Greene | Brassicaceae | 8 |
| Physaria purpurea | (A.Gray) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria rectipes | (Wooton & Standl.) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physocarpus monogynus | (Torr.) J.M.Coult. | Rosaceae | 8 |
| Physocarpus opulifolius | (L.) Maxim. | Rosaceae | 8 |
| Phytolacca americana | L. | Phytolaccaceae | 8 |
| Picea engelmannii | Parry ex Engelm. | Pinaceae | 8 |
| Picea pungens | Engelm. | Pinaceae | 8 |
| Picradeniopsis absinthifolia | (Benth.) B.G.Baldwin | Asteraceae | 8 |
| Picradeniopsis multiflora | (Hook. & Arn.) B.G.Baldwin | Asteraceae | 8 |
| Picradeniopsis oppositifolia | (Nutt.) Rydb. | Asteraceae | 8 |
| Picrothamnus desertorum | Nutt. | Asteraceae | 8 |
| Pictarena rotundata | (Wooton) Becklund | Fabaceae | 8 |
| Pilostyles thurberi | A.Gray | Apodanthaceae | 8 |
| Pinaropappus roseus | (Less.) Less. | Asteraceae | 8 |
| Pinus aristata | Engelm. | Pinaceae | 8 |
| Pinus arizonica | Engelm. | Pinaceae | 8 |
| Pinus cembroides | Zucc. | Pinaceae | 8 |
| Pinus edulis | Engelm. | Pinaceae | 8 |
| Pinus engelmannii | Carrière | Pinaceae | 8 |
| Pinus flexilis | E.James | Pinaceae | 8 |
| Pinus leiophylla | Schiede ex Schltdl. & Cham. | Pinaceae | 8 |
| Pinus monophylla | Torr. & Frém. | Pinaceae | 8 |
| Pinus ponderosa | Douglas ex C.Lawson | Pinaceae | 8 |
| Piptatheropsis micrantha | (Trin. & Rupr.) Romasch., P.M.Peterson & Soreng | Poaceae | 8 |
| Piptochaetium fimbriatum | (Kunth) Hitchc. | Poaceae | 8 |
| Piptochaetium pringlei | (Beal) Parodi | Poaceae | 8 |
| Pisonia capitata | (S.Watson) Standl. | Nyctaginaceae | 8 |
| Plagiobothrys arizonicus | (A.Gray) Greene ex A.Gray | Boraginaceae | 8 |
| Plagiobothrys collinus | (Phil.) I.M.Johnst. | Boraginaceae | 8 |
| Plagiobothrys scouleri | (Hook. & Arn.) I.M.Johnst. | Boraginaceae | 8 |
| Plagiobothrys stipitatus | I.M.Johnst. | Boraginaceae | 8 |
| Plagiobothrys tenellus | (Nutt.) A.Gray | Boraginaceae | 8 |
| Plantago australis | Lam. | Plantaginaceae | 8 |
| Plantago elongata | Pursh | Plantaginaceae | 8 |
| Plantago ovata | Forssk. | Plantaginaceae | 8 |
| Plantago patagonica | Jacq. | Plantaginaceae | 8 |
| Plantago rhodosperma | Decne. | Plantaginaceae | 8 |
| Plantago virginica | L. | Plantaginaceae | 8 |
| Plantago wrightiana | Decne. | Plantaginaceae | 8 |
| Platanthera purpurascens | (Rydb.) Sheviak & W.F.Jenn. | Orchidaceae | 8 |
| Platanthera sparsiflora | (S.Watson) Schltr. | Orchidaceae | 8 |
| Platanthera tescamnis | Sheviak & W.F.Jenn. | Orchidaceae | 8 |
| Platanus wrightii | S.Watson | Platanaceae | 8 |
| Platyschkuhria integrifolia | (A.Gray) Rydb. | Asteraceae | 8 |
| Platystemon californicus | Benth. | Papaveraceae | 8 |
| Plectocephalus americanus | (Nutt.) D.Don | Asteraceae | 8 |
| Pleiacanthus spinosus | (Nutt.) Rydb. | Asteraceae | 8 |
| Pleradenophora bilocularis | (S.Watson) Esser & A.L.Melo | Euphorbiaceae | 8 |
| Pleurocoronis pluriseta | (A.Gray) R.M.King & H.Rob. | Asteraceae | 8 |
| Pluchea odorata | (L.) Cass. | Asteraceae | 8 |
| Pluchea sericea | (Nutt.) Coville | Asteraceae | 8 |
| Plumbago zeylanica | L. | Plumbaginaceae | 8 |
| Poa bigelovii | Vasey ex Scribn. | Poaceae | 8 |
| Poa fendleriana | (Steud.) Vasey | Poaceae | 8 |
| Poa glauca | Vahl | Poaceae | 8 |
| Poa interior | Rydb. | Poaceae | 8 |
| Poa nemoralis | L. | Poaceae | 8 |
| Poa palustris | L. | Poaceae | 8 |
| Poa pratensis | L. | Poaceae | 8 |
| Poa secunda | J.Presl | Poaceae | 8 |
| Polemonium foliosissimum | A.Gray | Polemoniaceae | 8 |
| Polemonium pauciflorum | S.Watson | Polemoniaceae | 8 |
| Polemonium pulcherrimum | Hook. | Polemoniaceae | 8 |
| Polemonium viscosum | Nutt. | Polemoniaceae | 8 |
| Poliomintha incana | (Torr.) A.Gray | Lamiaceae | 8 |
| Polygonatum biflorum | (Walter) Elliott | Asparagaceae | 8 |
| Polygonum aviculare | L. | Polygonaceae | 8 |
| Polypodium hesperium | Maxon | Polypodiaceae | 8 |
| Polypogon interruptus | Kunth | Poaceae | 8 |
| Polystemma cordifolium | (A.Gray) McDonnell & Fishbein | Apocynaceae | 8 |
| Polystichum lonchitis | (L.) Roth | Dryopteridaceae | 8 |
| Polystichum scopulinum | (D.C.Eaton) Maxon | Dryopteridaceae | 8 |
| Pomaria jamesii | (Torr. & A.Gray) Walp. | Fabaceae | 8 |
| Pombalia glabra | (Dowell) Paula-Souza | Violaceae | 8 |
| Pombalia verticillata | (Ortega) Paula-Souza | Violaceae | 8 |
| Populus angustifolia | E.James | Salicaceae | 8 |
| Populus deltoides | W.Bartram ex Marshall | Salicaceae | 8 |
| Populus fremontii | S.Watson | Salicaceae | 8 |
| Populus tremuloides | Michx. | Salicaceae | 8 |
| Porophyllum gracile | Benth. | Asteraceae | 8 |
| Porophyllum ruderale | (Jacq.) Cass. | Asteraceae | 8 |
| Porterella carnosula | (Hook. & Arn.) Torr. | Campanulaceae | 8 |
| Portulaca halimoides | L. | Portulacaceae | 8 |
| Portulaca pilosa | L. | Portulacaceae | 8 |
| Portulaca suffrutescens | Engelm. | Portulacaceae | 8 |
| Portulaca umbraticola | Kunth | Portulacaceae | 8 |
| Potamogeton berchtoldii | Fieber | Potamogetonaceae | 8 |
| Potamogeton diversifolius | Raf. | Potamogetonaceae | 8 |
| Potamogeton foliosus | Raf. | Potamogetonaceae | 8 |
| Potamogeton gramineus | L. | Potamogetonaceae | 8 |
| Potamogeton natans | L. | Potamogetonaceae | 8 |
| Potamogeton nodosus | Poir. | Potamogetonaceae | 8 |
| Potamogeton pusillus | L. | Potamogetonaceae | 8 |
| Potentilla bicrenata | Rydb. | Rosaceae | 8 |
| Potentilla biennis | Greene | Rosaceae | 8 |
| Potentilla concinna | Richardson | Rosaceae | 8 |
| Potentilla crinita | A.Gray | Rosaceae | 8 |
| Potentilla gracilis | Douglas ex Hook. | Rosaceae | 8 |
| Potentilla hippiana | Lehm. | Rosaceae | 8 |
| Potentilla nivea | L. | Rosaceae | 8 |
| Potentilla norvegica | L. | Rosaceae | 8 |
| Potentilla pensylvanica | L. | Rosaceae | 8 |
| Potentilla pulcherrima | Lehm. | Rosaceae | 8 |
| Potentilla rivalis | Nutt. | Rosaceae | 8 |
| Potentilla sabulosa | M.E.Jones | Rosaceae | 8 |
| Potentilla thurberi | A.Gray | Rosaceae | 8 |
| Prenanthella exigua | (A.Gray) Rydb. | Asteraceae | 8 |
| Primula parryi | A.Gray | Primulaceae | 8 |
| Primula pauciflora | (Greene) A.R.Mast & Reveal | Primulaceae | 8 |
| Primula rusbyi | Greene | Primulaceae | 8 |
| Primula specuicola | Rydb. | Primulaceae | 8 |
| Primula tetrandra | (Suksd.) A.R.Mast & Reveal | Primulaceae | 8 |
| Proatriplex pleiantha | (W.A.Weber) Stutz & G.L.Chu | Chenopodiaceae | 8 |
| Proboscidea althaeifolia | (Benth.) Decne. | Martyniaceae | 8 |
| Proboscidea parviflora | (Wooton) Wooton & Standl. | Martyniaceae | 8 |
| Prosartes trachycarpa | S.Watson | Liliaceae | 8 |
| Prunella vulgaris | L. | Lamiaceae | 8 |
| Prunus emarginata | (Douglas ex Hook.) Eaton | Rosaceae | 8 |
| Prunus fasciculata | (Torr.) A.Gray | Rosaceae | 8 |
| Prunus serotina | Ehrh. | Rosaceae | 8 |
| Prunus virginiana | L. | Rosaceae | 8 |
| Psacalium decompositum | (A.Gray) H.Rob. & Brettell | Asteraceae | 8 |
| Psathyrotes annua | (Nutt.) A.Gray | Asteraceae | 8 |
| Psathyrotes pilifera | A.Gray | Asteraceae | 8 |
| Psathyrotes ramosissima | A.Gray | Asteraceae | 8 |
| Pseudognaphalium canescens | (DC.) Anderb. | Asteraceae | 8 |
| Pseudognaphalium leucocephalum | (A.Gray) Anderb. | Asteraceae | 8 |
| Pseudognaphalium macounii | (Greene) Kartesz | Asteraceae | 8 |
| Pseudognaphalium stramineum | (Kunth) Anderb. | Asteraceae | 8 |
| Pseudoroegneria spicata | (Pursh) Á.Löve | Poaceae | 8 |
| Pseudorontium cyathiferum | (Benth.) Rothm. | Plantaginaceae | 8 |
| Pseudotsuga menziesii | (Mirb.) Franco | Pinaceae | 8 |
| Psilactis asteroides | A.Gray | Asteraceae | 8 |
| Psilostrophe cooperi | (A.Gray) Greene | Asteraceae | 8 |
| Psilostrophe sparsiflora | (A.Gray) A.Nelson | Asteraceae | 8 |
| Psilostrophe tagetina | (Nutt.) Greene | Asteraceae | 8 |
| Psilotum nudum | (L.) P.Beauv. | Psilotaceae | 8 |
| Psorodendron fremontii | (Torr. ex A.Gray) Rydb. | Fabaceae | 8 |
| Psorodendron schottii | (Torr.) Rydb. | Fabaceae | 8 |
| Psorodendron spinosum | (A.Gray) Rydb. | Fabaceae | 8 |
| Psorothamnus emoryi | (A.Gray) Rydb. | Fabaceae | 8 |
| Psorothamnus scoparius | (A.Gray) Rydb. | Fabaceae | 8 |
| Ptelea trifoliata | L. | Rutaceae | 8 |
| Pteridium aquilinum | (L.) Kuhn | Dennstaedtiaceae | 8 |
| Pterospora andromedea | Nutt. | Ericaceae | 8 |
| Pterostegia drymarioides | Fisch. & C.A.Mey. | Polygonaceae | 8 |
| Puccinellia nuttalliana | (Schult.) Hitchc. | Poaceae | 8 |
| Purshia glandulosa | Curran | Rosaceae | 8 |
| Purshia stansburyana | (Torr.) Henrickson | Rosaceae | 8 |
| Purshia tridentata | (Pursh) DC. | Rosaceae | 8 |
| Pyrola chlorantha | Sw. | Ericaceae | 8 |
| Pyrola elliptica | Nutt. | Ericaceae | 8 |
| Pyrola minor | L. | Ericaceae | 8 |
| Pyrola picta | Sm. | Ericaceae | 8 |
| Pyrrocoma crocea | (A.Gray) Greene | Asteraceae | 8 |
| Quercus arizonica | Sarg. | Fagaceae | 8 |
| Quercus chrysolepis | Liebm. | Fagaceae | 8 |
| Quercus emoryi | Torr. | Fagaceae | 8 |
| Quercus gambelii | Nutt. | Fagaceae | 8 |
| Quercus grisea | Liebm. | Fagaceae | 8 |
| Quercus hypoleucoides | A.Camus | Fagaceae | 8 |
| Quercus oblongifolia | Torr. | Fagaceae | 8 |
| Quercus palmeri | (Engelm.) Engelm. | Fagaceae | 8 |
| Quercus pungens | Liebm. | Fagaceae | 8 |
| Quercus rugosa | Née | Fagaceae | 8 |
| Quercus toumeyi | Sarg. | Fagaceae | 8 |
| Quercus turbinella | Greene | Fagaceae | 8 |
| Quincula lobata | (Torr.) Raf. | Solanaceae | 8 |
| Rafinesquia californica | Nutt. | Asteraceae | 8 |
| Rafinesquia neomexicana | A.Gray | Asteraceae | 8 |
| Ranunculus cardiophyllus | Hook. | Ranunculaceae | 8 |
| Ranunculus eschscholtzii | Schltdl. | Ranunculaceae | 8 |
| Ranunculus flammula | L. | Ranunculaceae | 8 |
| Ranunculus glaberrimus | Hook. | Ranunculaceae | 8 |
| Ranunculus inamoenus | Greene | Ranunculaceae | 8 |
| Ranunculus macounii | Britton | Ranunculaceae | 8 |
| Ranunculus minimus | E.H.L.Krause | Ranunculaceae | 8 |
| Ranunculus pensylvanicus | L.f. | Ranunculaceae | 8 |
| Ranunculus petiolaris | Kunth | Ranunculaceae | 8 |
| Ranunculus sceleratus | L. | 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 |
| Rhamnus crocea | Nutt. | Rhamnaceae | 8 |
| Rhinotropis intermontana | (T.Wendt) J.R.Abbott | Polygalaceae | 8 |
| Rhinotropis lindheimeri | (A.Gray) J.R.Abbott | Polygalaceae | 8 |
| Rhinotropis subspinosa | (S.Watson) J.R.Abbott | Polygalaceae | 8 |
| Rhodiola rhodantha | (A.Gray) H.Jacobsen | Crassulaceae | 8 |
| Rhus aromatica | Aiton | Anacardiaceae | 8 |
| Rhus copallinum | L. | Anacardiaceae | 8 |
| Rhus glabra | L. | Anacardiaceae | 8 |
| Rhus microphylla | Engelm. | Anacardiaceae | 8 |
| Rhus ovata | S.Watson | Anacardiaceae | 8 |
| Rhus virens | Lindh. ex A.Gray | Anacardiaceae | 8 |
| Rhynchosia edulis | Griseb. | 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 |
| Ribes aureum | Pursh | Grossulariaceae | 8 |
| Ribes cereum | Douglas | Grossulariaceae | 8 |
| Ribes inerme | Rydb. | Grossulariaceae | 8 |
| Ribes leptanthum | A.Gray | Grossulariaceae | 8 |
| Ribes montigenum | McClatchie | Grossulariaceae | 8 |
| Ribes pinetorum | Greene | Grossulariaceae | 8 |
| Ribes velutinum | Greene | Grossulariaceae | 8 |
| Ribes viscosissimum | Pursh | Grossulariaceae | 8 |
| Ribes wolfii | Rothr. | Grossulariaceae | 8 |
| Rivina humilis | L. | Petiveriaceae | 8 |
| Robinia neomexicana | A.Gray | Fabaceae | 8 |
| Roldana hartwegii | (Benth.) H.Rob. & Brettell | Asteraceae | 8 |
| Rorippa curvipes | Greene | Brassicaceae | 8 |
| Rorippa palustris | (L.) Besser | Brassicaceae | 8 |
| Rosa nutkana | C.Presl | Rosaceae | 8 |
| Rosa stellata | Wooton | Rosaceae | 8 |
| Rosa woodsii | Lindl. | Rosaceae | 8 |
| Rotala ramosior | (L.) Koehne | Lythraceae | 8 |
| Rubus deliciosus | Torr. | Rosaceae | 8 |
| Rubus flagellaris | Willd. | Rosaceae | 8 |
| Rubus idaeus | L. | Rosaceae | 8 |
| Rubus leucodermis | (Douglas ex Hook.) Douglas ex Torr. & A.Gray | Rosaceae | 8 |
| Rubus parviflorus | Nutt. | Rosaceae | 8 |
| Rudbeckia laciniata | L. | Asteraceae | 8 |
| Ruellia ciliatiflora | Hook. | 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 occidentalis | S.Watson | Polygonaceae | 8 |
| Rumex salicifolius | Weinm. | Polygonaceae | 8 |
| Rumex triangulivalvis | (Danser) Rech.f. | Polygonaceae | 8 |
| Rumex venosus | Pursh | Polygonaceae | 8 |
| Ruppia cirrhosa | (Petagna) Grande | Ruppiaceae | 8 |
| Sabulina douglasii | (Fenzl ex Torr. & A.Gray) Dillenb. & Kadereit | Caryophyllaceae | 8 |
| Sabulina rubella | (Wahlenb.) Dillenb. & Kadereit | Caryophyllaceae | 8 |
| Sagina saginoides | (L.) H.Karst. | Caryophyllaceae | 8 |
| Sagittaria cuneata | E.Sheld. | Alismataceae | 8 |
| Sagittaria longiloba | Engelm. ex J.G.Sm. | Alismataceae | 8 |
| Sairocarpus kingii | (S.Watson) D.A.Sutton | Plantaginaceae | 8 |
| Sairocarpus nuttallianus | (Benth.) D.A.Sutton | Plantaginaceae | 8 |
| Salix amygdaloides | Andersson | Salicaceae | 8 |
| Salix bebbiana | Sarg. | Salicaceae | 8 |
| Salix bonplandiana | Kunth | Salicaceae | 8 |
| Salix boothii | Dorn | Salicaceae | 8 |
| Salix exigua | Nutt. | Salicaceae | 8 |
| Salix geyeriana | Andersson | Salicaceae | 8 |
| Salix gooddingii | C.R.Ball | Salicaceae | 8 |
| Salix laevigata | Bebb | Salicaceae | 8 |
| Salix lasiandra | Benth. | Salicaceae | 8 |
| Salix lasiolepis | Benth. | Salicaceae | 8 |
| Salix lutea | Nutt. | Salicaceae | 8 |
| Salix planifolia | Pursh | Salicaceae | 8 |
| Salix scouleriana | Barratt | Salicaceae | 8 |
| Salix taxifolia | Kunth | Salicaceae | 8 |
| Salvia arizonica | A.Gray | Lamiaceae | 8 |
| Salvia azurea | Lam. ex Vahl | Lamiaceae | 8 |
| Salvia columbariae | Benth. | Lamiaceae | 8 |
| Salvia dorrii | (Kellogg) Abrams | Lamiaceae | 8 |
| Salvia henryi | A.Gray | Lamiaceae | 8 |
| Salvia microphylla | Kunth | Lamiaceae | 8 |
| Salvia mohavensis | Greene | Lamiaceae | 8 |
| Salvia pachyphylla | Epling ex Munz | Lamiaceae | 8 |
| Salvia reflexa | Hornem. | Lamiaceae | 8 |
| Salvia subincisa | Benth. | Lamiaceae | 8 |
| Salvia vaseyi | (Porter) Parish | Lamiaceae | 8 |
| Sambucus canadensis | L. | Viburnaceae | 8 |
| Sambucus cerulea | Raf. | Viburnaceae | 8 |
| Sambucus racemosa | L. | Viburnaceae | 8 |
| Samolus parviflorus | Raf. | Primulaceae | 8 |
| Sanguisorba occidentalis | Nutt. | Rosaceae | 8 |
| Sapindus drummondii | Hook. & Arn. | Sapindaceae | 8 |
| Sarcobatus vermiculatus | (Hook.) Torr. | Sarcobataceae | 8 |
| Saxifraga cespitosa | L. | Saxifragaceae | 8 |
| Saxifraga flagellaris | Willd. ex Sternb. | Saxifragaceae | 8 |
| Saxifraga hyperborea | R.Br. | Saxifragaceae | 8 |
| Sceptridium multifidum | (S.G.Gmel.) M.Nishida | Ophioglossaceae | 8 |
| Schistophragma intermedium | (A.Gray) Pennell | Plantaginaceae | 8 |
| Schizachyrium sanguineum | (Retz.) Alston | Poaceae | 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 |
| Schoenoplectus tabernaemontani | (C.C.Gmel.) Palla | Cyperaceae | 8 |
| Scirpus atrovirens | Willd. | Cyperaceae | 8 |
| Scirpus microcarpus | J.Presl & C.Presl | Cyperaceae | 8 |
| Scirpus pendulus | Muhl. | Cyperaceae | 8 |
| Sclerocactus intertextus | (Engelm.) N.P.Taylor | Cactaceae | 8 |
| Sclerocactus papyracanthus | (Engelm.) N.P.Taylor | Cactaceae | 8 |
| Sclerocactus parviflorus | Clover & Jotter | Cactaceae | 8 |
| Scleropogon brevifolius | Phil. | Poaceae | 8 |
| Scopulophila rixfordii | (Brandegee) Munz & I.M.Johnst. | Caryophyllaceae | 8 |
| Scrophularia californica | Cham. & Schltdl. | Scrophulariaceae | 8 |
| Scrophularia parviflora | Wooton & Standl. | Scrophulariaceae | 8 |
| Scutellaria galericulata | L. | Lamiaceae | 8 |
| Scutellaria lateriflora | L. | Lamiaceae | 8 |
| Scutellaria mexicana | (Torr.) A.J.Paton | Lamiaceae | 8 |
| Scutellaria potosina | Brandegee | Lamiaceae | 8 |
| Sedum cockerellii | Britton | Crassulaceae | 8 |
| Sedum lanceolatum | Torr. | Crassulaceae | 8 |
| Sedum stelliforme | S.Watson | Crassulaceae | 8 |
| Selaginella arizonica | Maxon | Selaginellaceae | 8 |
| Selaginella eremophila | Maxon | Selaginellaceae | 8 |
| Selaginella leucobryoides | Maxon | Selaginellaceae | 8 |
| Selaginella longipila | Hieron. | Selaginellaceae | 8 |
| Selaginella mutica | D.C.Eaton | Selaginellaceae | 8 |
| Selaginella rupincola | Underw. | Selaginellaceae | 8 |
| Selaginella scopulorum | Maxon | Selaginellaceae | 8 |
| Selaginella underwoodii | Hieron. | Selaginellaceae | 8 |
| Senecio bigelovii | A.Gray | Asteraceae | 8 |
| Senecio eremophilus | Richardson | Asteraceae | 8 |
| Senecio flaccidus | Less. | Asteraceae | 8 |
| Senecio lemmonii | A.Gray | Asteraceae | 8 |
| Senecio mohavensis | A.Gray | Asteraceae | 8 |
| Senecio spartioides | Torr. & A.Gray | Asteraceae | 8 |
| Senecio triangularis | Hook. | Asteraceae | 8 |
| Senecio wootonii | Greene | Asteraceae | 8 |
| Senegalia greggii | (A.Gray) Britton & Rose | Fabaceae | 8 |
| Senegalia wrightii | (Benth.) Britton & Rose | Fabaceae | 8 |
| Senna armata | (S.Watson) H.S.Irwin & Barneby | Fabaceae | 8 |
| Senna bauhinioides | (A.Gray) 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 wislizeni | (A.Gray) H.S.Irwin & Barneby | Fabaceae | 8 |
| Sesbania herbacea | (Mill.) McVaugh | Fabaceae | 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 |
| Setaria scheelei | (Steud.) Hitchc. | Poaceae | 8 |
| Shepherdia argentea | (Pursh) Nutt. | Elaeagnaceae | 8 |
| Shepherdia canadensis | (L.) Nutt. | Elaeagnaceae | 8 |
| Shepherdia rotundifolia | Parry | Elaeagnaceae | 8 |
| Sibbaldia procumbens | L. | Rosaceae | 8 |
| Sicyos laciniatus | L. | Cucurbitaceae | 8 |
| Sida spinosa | L. | Malvaceae | 8 |
| Sidalcea neomexicana | A.Gray | Malvaceae | 8 |
| Sideroxylon lanuginosum | Michx. | Sapotaceae | 8 |
| Silene acaulis | (L.) Jacq. | Caryophyllaceae | 8 |
| Silene antirrhina | L. | Caryophyllaceae | 8 |
| Silene drummondii | Hook. | Caryophyllaceae | 8 |
| Silene laciniata | Cav. | Caryophyllaceae | 8 |
| Silene menziesii | Hook. | 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 |
| Sisyrinchium demissum | Greene | Iridaceae | 8 |
| Sisyrinchium idahoense | E.P.Bicknell | Iridaceae | 8 |
| Sium suave | Walter | Apiaceae | 8 |
| Solanum americanum | Mill. | Solanaceae | 8 |
| Solanum deflexum | Greenm. | Solanaceae | 8 |
| Solanum douglasii | Dunal | Solanaceae | 8 |
| Solanum elaeagnifolium | Cav. | Solanaceae | 8 |
| Solanum emulans | Raf. | Solanaceae | 8 |
| Solanum hindsianum | Benth. | Solanaceae | 8 |
| Solanum jamesii | Torr. | Solanaceae | 8 |
| Solanum rostratum | Dunal | Solanaceae | 8 |
| Solanum stoloniferum | Schltdl. | Solanaceae | 8 |
| Solanum triflorum | Nutt. | Solanaceae | 8 |
| Solanum umbelliferum | Eschsch. | Solanaceae | 8 |
| Solidago canadensis | L. | Asteraceae | 8 |
| Solidago elongata | Nutt. | Asteraceae | 8 |
| Solidago lepida | DC. | Asteraceae | 8 |
| Solidago missouriensis | Nutt. | Asteraceae | 8 |
| Solidago multiradiata | Aiton | Asteraceae | 8 |
| Solidago simplex | Kunth | Asteraceae | 8 |
| Solidago velutina | DC. | Asteraceae | 8 |
| Solidago wrightii | A.Gray | Asteraceae | 8 |
| Sophora nuttalliana | B.L.Turner | Fabaceae | 8 |
| Sophora stenophylla | A.Gray | Fabaceae | 8 |
| Sorbus scopulina | Greene | Rosaceae | 8 |
| Sorghastrum nutans | (L.) Nash | Poaceae | 8 |
| Sparganium angustifolium | Michx. | Typhaceae | 8 |
| Sparganium emersum | Rehmann | Typhaceae | 8 |
| Sparganium eurycarpum | Engelm. | Typhaceae | 8 |
| Spergularia marina | (L.) Besser | Caryophyllaceae | 8 |
| Spermolepis lateriflora | G.L.Nesom | Apiaceae | 8 |
| Sphaeralcea ambigua | A.Gray | Malvaceae | 8 |
| Sphaeralcea coccinea | (Nutt.) Rydb. | 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 grossulariifolia | (Hook. & Arn.) Rydb. | 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 parvifolia | A.Nelson | Malvaceae | 8 |
| Sphaeralcea polychroma | La Duke | Malvaceae | 8 |
| Sphaeralcea rusbyi | A.Gray | Malvaceae | 8 |
| Sphenopholis intermedia | (Rydb.) Rydb. | Poaceae | 8 |
| Sphenopholis interrupta | (Buckley) Scribn. | Poaceae | 8 |
| Sphenopholis obtusata | (Michx.) Scribn. | Poaceae | 8 |
| Spinulum annotinum | (L.) A.Haines | Lycopodiaceae | 8 |
| Spiranthes romanzoffiana | Cham. | Orchidaceae | 8 |
| Spirodela polyrhiza | (L.) Schleid. | Araceae | 8 |
| Sporobolus airoides | (Torr.) Torr. | Poaceae | 8 |
| Sporobolus arenicola | P.M.Peterson | Poaceae | 8 |
| Sporobolus compositus | (Poir.) Merr. | Poaceae | 8 |
| Sporobolus contractus | Hitchc. | Poaceae | 8 |
| Sporobolus cryptandrus | (Torr.) A.Gray | Poaceae | 8 |
| Sporobolus flexuosus | (Vasey) Rydb. | Poaceae | 8 |
| Sporobolus giganteus | Nash | Poaceae | 8 |
| Sporobolus hookerianus | P.M.Peterson & Saarela | Poaceae | 8 |
| Sporobolus junceus | (P.Beauv.) Kunth | Poaceae | 8 |
| Sporobolus nealleyi | Vasey | Poaceae | 8 |
| Sporobolus neglectus | Nash | Poaceae | 8 |
| Sporobolus pyramidatus | (Lam.) Hitchc. | Poaceae | 8 |
| Sporobolus vaginiflorus | (Torr. ex A.Gray) Alph.Wood | Poaceae | 8 |
| Sporobolus wrightii | Scribn. | Poaceae | 8 |
| Stachys coccinea | Ortega | Lamiaceae | 8 |
| Stachys pilosa | Nutt. | Lamiaceae | 8 |
| Stanleya elata | M.E.Jones | Brassicaceae | 8 |
| Stanleya pinnata | (Pursh) Britton | Brassicaceae | 8 |
| Stebbinsoseris heterocarpa | (Nutt.) K.L.Chambers | Asteraceae | 8 |
| Stellaria longifolia | Muhl. ex Willd. | Caryophyllaceae | 8 |
| Stellaria longipes | Goldie | Caryophyllaceae | 8 |
| Stellaria nitens | Nutt. | Caryophyllaceae | 8 |
| Stemodia durantifolia | (L.) Sw. | Plantaginaceae | 8 |
| Stenocereus thurberi | (Engelm.) Buxb. | Cactaceae | 8 |
| Stenogonum salsuginosum | Nutt. | Polygonaceae | 8 |
| Stenotus acaulis | (Nutt.) Nutt. | Asteraceae | 8 |
| Stenotus armerioides | Nutt. | Asteraceae | 8 |
| Stephanomeria exigua | Nutt. | Asteraceae | 8 |
| Stephanomeria parryi | A.Gray | Asteraceae | 8 |
| Stephanomeria pauciflora | (Torr.) A.Nelson | Asteraceae | 8 |
| Stephanomeria thurberi | A.Gray | Asteraceae | 8 |
| Stevia plummerae | A.Gray | Asteraceae | 8 |
| Stevia serrata | Cav. | Asteraceae | 8 |
| Stevia viscida | Kunth | Asteraceae | 8 |
| Stillingia linearifolia | S.Watson | Euphorbiaceae | 8 |
| Stillingia paucidentata | S.Watson | Euphorbiaceae | 8 |
| Stillingia spinulosa | Torr. | Euphorbiaceae | 8 |
| Streptanthus carinatus | Wright ex A.Gray | Brassicaceae | 8 |
| Streptanthus cooperi | (S.Watson) Al-Shehbaz | Brassicaceae | 8 |
| Streptanthus cordatus | Nutt. | Brassicaceae | 8 |
| Streptanthus crassicaulis | Torr. | Brassicaceae | 8 |
| Streptanthus lasiophyllus | Hook. & Arn. ex Hoover | Brassicaceae | 8 |
| Streptanthus longirostris | (S.Watson) S.Watson | Brassicaceae | 8 |
| Streptopus amplexifolius | (L.) DC. | Liliaceae | 8 |
| Strombocarpa pubescens | (Benth.) A.Gray | Fabaceae | 8 |
| Stuckenia filiformis | (Pers.) Börner | Potamogetonaceae | 8 |
| Stuckenia pectinata | (L.) Börner | Potamogetonaceae | 8 |
| Stylocline gnaphalioides | Nutt. | Asteraceae | 8 |
| Stylocline micropoides | A.Gray | Asteraceae | 8 |
| Stylocline sonorensis | Wiggins | Asteraceae | 8 |
| Suaeda calceoliformis | (Hook.) Moq. | Chenopodiaceae | 8 |
| Suaeda nigra | (Raf.) J.F.Macbr. | Chenopodiaceae | 8 |
| Swertia perennis | L. | Gentianaceae | 8 |
| Symphoricarpos longiflorus | A.Gray | Caprifoliaceae | 8 |
| Symphoricarpos rotundifolius | A.Gray | Caprifoliaceae | 8 |
| Symphyotrichum ascendens | (Lindl.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum eatonii | (A.Gray) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum ericoides | (L.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum falcatum | (Lindl.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum foliaceum | (Lindl. ex DC.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum frondosum | (Nutt.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum lanceolatum | (Willd.) G.L.Nesom | Asteraceae | 8 |
| Tagetes lemmonii | A.Gray | Asteraceae | 8 |
| Tagetes micrantha | Cav. | Asteraceae | 8 |
| Talinum aurantiacum | Engelm. | Talinaceae | 8 |
| Talinum paniculatum | (Jacq.) Gaertn. | Talinaceae | 8 |
| Tecoma stans | (L.) Juss. | Bignoniaceae | 8 |
| Tephrosia thurberi | (Rydb.) C.E.Wood | Fabaceae | 8 |
| Tetracoccus hallii | Brandegee | Picrodendraceae | 8 |
| Tetradymia canescens | DC. | Asteraceae | 8 |
| Tetramerium nervosum | Nees | Acanthaceae | 8 |
| Tetraneuris acaulis | Greene | Asteraceae | 8 |
| Tetraneuris argentea | Greene | Asteraceae | 8 |
| Tetraneuris ivesiana | Greene | Asteraceae | 8 |
| Teucrium canadense | L. | Lamiaceae | 8 |
| Teucrium depressum | Small | Lamiaceae | 8 |
| Teucrium glandulosum | Kellogg | Lamiaceae | 8 |
| Teucrium laciniatum | Torr. | Lamiaceae | 8 |
| Thalictrum dasycarpum | Fisch., C.A.Mey. & Avé-Lall. | Ranunculaceae | 8 |
| Thalictrum fendleri | Engelm. ex A.Gray | Ranunculaceae | 8 |
| Thalictrum revolutum | DC. | Ranunculaceae | 8 |
| Thamnosma montana | Torr. & Frém. | Rutaceae | 8 |
| Thelesperma longipes | A.Gray | Asteraceae | 8 |
| Thelesperma megapotamicum | (Spreng.) Kuntze | Asteraceae | 8 |
| Thelesperma subnudum | A.Gray | Asteraceae | 8 |
| Thelypodium integrifolium | (Nutt.) Endl. | Brassicaceae | 8 |
| Thermopsis montana | Nutt. | Fabaceae | 8 |
| Thymophylla acerosa | (DC.) Strother | Asteraceae | 8 |
| Thymophylla concinna | (A.Gray) Strother | Asteraceae | 8 |
| Thymophylla pentachaeta | (DC.) Small | Asteraceae | 8 |
| Thysanocarpus curvipes | Hook. | Brassicaceae | 8 |
| Thysanocarpus laciniatus | Nutt. | Brassicaceae | 8 |
| Tidestromia lanuginosa | (Nutt.) Standl. | Amaranthaceae | 8 |
| Tidestromia suffruticosa | (Torr.) Standl. | Amaranthaceae | 8 |
| Tillandsia recurvata | (L.) L. | Bromeliaceae | 8 |
| Tiquilia canescens | (DC.) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia latior | (I.M.Johnst.) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia nuttallii | (Hook.) 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 |
| Tomostima cuneifolia | (Nutt. ex Torr. & A.Gray) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Tomostima platycarpa | (Torr. & A.Gray) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Tomostima reptans | (Lam.) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Torreyostellaria jamesiana | (Torr.) Gang Yao, B.Xue & Z.Q.Song | Caryophyllaceae | 8 |
| Townsendia annua | Beaman | Asteraceae | 8 |
| Townsendia exscapa | (Richardson) Porter | Asteraceae | 8 |
| Townsendia incana | Nutt. | Asteraceae | 8 |
| Toxicodendron radicans | (L.) Kuntze | Anacardiaceae | 8 |
| Toxicoscordion paniculatum | (Nutt.) Rydb. | Melanthiaceae | 8 |
| Trachypogon spicatus | (L.f.) Kuntze | Poaceae | 8 |
| Tradescantia occidentalis | (Britton) Smyth | 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 |
| Trautvetteria caroliniensis | (Walter) Vail | Ranunculaceae | 8 |
| Trianthema portulacastrum | L. | Aizoaceae | 8 |
| Tricardia watsonii | Torr. ex S.Watson | Hydrophyllaceae | 8 |
| Trichogalium boreale | (L.) Fourr. | Rubiaceae | 8 |
| Trichogalium fendleri | (A.Gray) Kadereit & Schneew. | Rubiaceae | 8 |
| Trichoptilium incisum | (A.Gray) A.Gray | Asteraceae | 8 |
| Trichostema arizonicum | A.Gray | Lamiaceae | 8 |
| Tridens albescens | (Vasey) Wooton & Standl. | Poaceae | 8 |
| Tridentopsis mutica | (Torr.) P.M.Peterson | Poaceae | 8 |
| Trifolium albopurpureum | Torr. & A.Gray | Fabaceae | 8 |
| Trifolium amabile | Kunth | Fabaceae | 8 |
| Trifolium gracilentum | Torr. & A.Gray | Fabaceae | 8 |
| Trifolium gymnocarpon | Nutt. | Fabaceae | 8 |
| Trifolium longipes | Nutt. | Fabaceae | 8 |
| Trifolium microcephalum | Pursh | 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 palustris | L. | Juncaginaceae | 8 |
| Triodanis holzingeri | McVaugh | Campanulaceae | 8 |
| Triodanis perfoliata | (L.) Nieuwl. | Campanulaceae | 8 |
| Triplasiella eragrostoides | (Vasey & Scribn.) P.M.Peterson & Romasch. | Poaceae | 8 |
| Triteleia lemmoniae | (S.Watson) Greene | Asparagaceae | 8 |
| Triteleiopsis palmeri | (S.Watson) Hoover | Asparagaceae | 8 |
| Trixis californica | Kellogg | Asteraceae | 8 |
| Turritis glabra | L. | Brassicaceae | 8 |
| Typha domingensis | Pers. | Typhaceae | 8 |
| Typha latifolia | L. | Typhaceae | 8 |
| Urochloa arizonica | (Scribn. & Merr.) Morrone & Zuloaga | Poaceae | 8 |
| Urochloa platyphylla | (Munro ex C.Wright) R.D.Webster | Poaceae | 8 |
| Uropappus lindleyi | (DC.) Nutt. | Asteraceae | 8 |
| Urtica gracilenta | Greene | Urticaceae | 8 |
| Urtica gracilis | Aiton | Urticaceae | 8 |
| Utricularia macrorhiza | Leconte | Lentibulariaceae | 8 |
| Utricularia minor | L. | Lentibulariaceae | 8 |
| Vaccinium myrtillus | L. | Ericaceae | 8 |
| Vachellia constricta | (Benth.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia farnesiana | (L.) Wight & Arn. | Fabaceae | 8 |
| Vachellia vernicosa | (Britton & Rose) Seigler & Ebinger | Fabaceae | 8 |
| Valeriana acutiloba | Rydb. | Caprifoliaceae | 8 |
| Valeriana arizonica | A.Gray | Caprifoliaceae | 8 |
| Valeriana ciliosa | (Greene) Byng & Christenh. | Caprifoliaceae | 8 |
| Valeriana edulis | Nutt. | Caprifoliaceae | 8 |
| Valeriana occidentalis | A.Heller | Caprifoliaceae | 8 |
| Valeriana sorbifolia | Kunth | Caprifoliaceae | 8 |
| Veratrum californicum | Durand | Melanthiaceae | 8 |
| Verbena bipinnatifida | (Nutt.) Schauer | Verbenaceae | 8 |
| Verbena bracteata | Cav. ex Lag. & Rodr. | Verbenaceae | 8 |
| Verbena carolina | L. | Verbenaceae | 8 |
| Verbena chiricahensis | (Umber) Moldenke | Verbenaceae | 8 |
| Verbena elegans | Kunth | Verbenaceae | 8 |
| Verbena gooddingii | Briq. | Verbenaceae | 8 |
| Verbena hastata | L. | 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 stricta | Vent. | Verbenaceae | 8 |
| Verbena urticifolia | L. | Verbenaceae | 8 |
| Verbena xutha | Lehm. | Verbenaceae | 8 |
| Verbesina longifolia | A.Gray | Asteraceae | 8 |
| Verbesina rothrockii | B.L.Rob. & Greenm. | Asteraceae | 8 |
| Veronica americana | (Raf.) Schwein. ex Benth. | Plantaginaceae | 8 |
| Veronica peregrina | L. | Plantaginaceae | 8 |
| Veronica plantaginea | E.James | Plantaginaceae | 8 |
| Veronica scutellata | L. | Plantaginaceae | 8 |
| Veronica serpyllifolia | L. | Plantaginaceae | 8 |
| Veronica wormskjoldii | Roem. & Schult. | Plantaginaceae | 8 |
| Vesper bulbosus | (A.Nelson) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vesper constancei | (R.L.Hartm.) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vesper multinervatus | (J.M.Coult. & Rose) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vesper purpurascens | (A.Gray) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vicia americana | Muhl. ex Willd. | Fabaceae | 8 |
| Vicia ludoviciana | Nutt. | Fabaceae | 8 |
| Vicia pulchella | Kunth | Fabaceae | 8 |
| Viguiera dentata | (Cav.) Spreng. | Asteraceae | 8 |
| Viola adunca | Sm. | Violaceae | 8 |
| Viola canadensis | L. | Violaceae | 8 |
| Viola macloskeyi | F.E.Lloyd | Violaceae | 8 |
| Viola nephrophylla | Greene | Violaceae | 8 |
| Viola nuttallii | Pursh | Violaceae | 8 |
| Viola pedatifida | G.Don | Violaceae | 8 |
| Viola purpurea | Kellogg | Violaceae | 8 |
| Viola rafinesquei | Greene | Violaceae | 8 |
| Vitis arizonica | Engelm. | Vitaceae | 8 |
| Waltheria indica | L. | Malvaceae | 8 |
| Washingtonia filifera | (Rafarin) H.Wendl. ex de Bary | Arecaceae | 8 |
| Woodsia neomexicana | Windham | Woodsiaceae | 8 |
| Woodsia oregana | D.C.Eaton | Woodsiaceae | 8 |
| Woodsia phillipsii | Windham | Woodsiaceae | 8 |
| Woodsia scopulina | D.C.Eaton | Woodsiaceae | 8 |
| Woodwardia fimbriata | Sm. | Blechnaceae | 8 |
| Wyethia arizonica | A.Gray | Asteraceae | 8 |
| Xanthisma gracile | (Nutt.) D.R.Morgan & R.L.Hartm. | Asteraceae | 8 |
| Xanthisma grindelioides | (Nutt.) 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 |
| Xylorhiza tortifolia | Greene | Asteraceae | 8 |
| Yabea microcarpa | Koso-Pol. | Apiaceae | 8 |
| Yucca angustissima | Engelm. ex Trel. | Asparagaceae | 8 |
| Yucca baccata | Torr. | Asparagaceae | 8 |
| Yucca baileyi | Wooton & Standl. | Asparagaceae | 8 |
| Yucca brevifolia | Engelm. | Asparagaceae | 8 |
| Yucca elata | (Engelm.) Engelm. | Asparagaceae | 8 |
| Yucca harrimaniae | Trel. | Asparagaceae | 8 |
| Yucca madrensis | Gentry | Asparagaceae | 8 |
| Yucca schidigera | Roezl ex Ortgies | Asparagaceae | 8 |
| Yucca utahensis | McKelvey | Asparagaceae | 8 |
| Zannichellia palustris | L. | Potamogetonaceae | 8 |
| Zapoteca formosa | (Kunth) H.M.Hern. | Fabaceae | 8 |
| Zeltnera arizonica | (A.Gray) G.Mans. | Gentianaceae | 8 |
| Zinnia acerosa | (DC.) A.Gray | Asteraceae | 8 |
| Zinnia grandiflora | Nutt. | Asteraceae | 8 |
| Zinnia peruviana | (L.) L. | Asteraceae | 8 |
| Zizania palustris | L. | Poaceae | 8 |
| Zornia reticulata | Sm. | Fabaceae | 8 |
| Zuloagaea bulbosa | (Kunth) Bess | Poaceae | 8 |
| Zygophyllum laeve | (Standl.) Christenh. & Byng | Zygophyllaceae | 8 |
| Zygophyllum pachyacanthum | (Rydb.) Christenh. & Byng | Zygophyllaceae | 8 |
| Agave phillipsiana | W.C.Hodgs. | Asparagaceae | 7 |
| Baccharis bigelovii | A.Gray | Asteraceae | 7 |
| Boerhavia spicata | Choisy | Nyctaginaceae | 7 |
| Bouteloua radicosa | (E.Fourn.) Griffiths | Poaceae | 7 |
| Brickellia brachyphylla | (A.Gray) A.Gray | Asteraceae | 7 |
| Bromus marginatus | Nees ex Steud. | Poaceae | 7 |
| Camissoniopsis confusa | (P.H.Raven) W.L.Wagner & Hoch | Onagraceae | 7 |
| Carex simulata | Mack. | Cyperaceae | 7 |
| Cordylanthus parviflorus | (Ferris) Wiggins | Orobanchaceae | 7 |
| Corispermum americanum | (Nutt.) Nutt. | Chenopodiaceae | 7 |
| Crepis runcinata | (E.James) Torr. & A.Gray | Asteraceae | 7 |
| Cryptantha ganderi | I.M.Johnst. | Boraginaceae | 7 |
| Cylindropuntia abyssi | (Hester) Backeb. | Cactaceae | 7 |
| Cymopterus newberryi | M.E.Jones | Apiaceae | 7 |
| Cyperus pallidicolor | (Kük.) G.C.Tucker | Cyperaceae | 7 |
| Dalea filiformis | A.Gray | Fabaceae | 7 |
| Drymaria pachyphylla | Wooton & Standl. | Caryophyllaceae | 7 |
| Elionurus barbiculmis | Hack. ex Scribn. | Poaceae | 7 |
| Erigeron pulcherrimus | A.Heller | Asteraceae | 7 |
| Eriochloa acuminata | (J.Presl) Kunth | Poaceae | 7 |
| Eriogonum leptocladon | Torr. & A.Gray | Polygonaceae | 7 |
| Festuca saximontana | Rydb. | Poaceae | 7 |
| Frangula betulifolia | (Greene) Grubov | Rhamnaceae | 7 |
| Gomphrena nitida | Rothr. | Amaranthaceae | 7 |
| Hibiscus biseptus | S.Watson | Malvaceae | 7 |
| Linanthus bigelovii | (A.Gray) Greene | Polemoniaceae | 7 |
| Mariosousa millefolia | (S.Watson) Seigler & Ebinger | Fabaceae | 7 |
| Melampodium longicorne | A.Gray | Asteraceae | 7 |
| Mentzelia jonesii | (Urb. & Gilg) H.J.Thomps. & J.E.Roberts | Loasaceae | 7 |
| Monardella linoides | A.Gray | Lamiaceae | 7 |
| Opuntia martiniana | (L.D.Benson) B.D.Parfitt | Cactaceae | 7 |
| Penstemon deaveri | Crosswh. | Plantaginaceae | 7 |
| Phacelia filiformis | Brand | Hydrophyllaceae | 7 |
| Phacelia pinkavae | N.D.Atwood | Hydrophyllaceae | 7 |
| Phacelia serrata | J.W.Voss | Hydrophyllaceae | 7 |
| Physalis caudella | Standl. | Solanaceae | 7 |
| Plantago eriopoda | Torr. | Plantaginaceae | 7 |
| Psorothamnus thompsoniae | (Vail) R.L.Welsh & N.D.Atwood | Fabaceae | 7 |
| Rumex orthoneurus | Rech.f. | Polygonaceae | 7 |
| Sageretia wrightii | S.Watson | Rhamnaceae | 7 |
| Scirpus pallidus | (Britton) Fernald | Cyperaceae | 7 |
| Senecio riddellii | Torr. & A.Gray | Asteraceae | 7 |
| Sida neomexicana | A.Gray | Malvaceae | 7 |
| Townsendia formosa | Greene | Asteraceae | 7 |
| Tripterocalyx wootonii | Standl. | Nyctaginaceae | 7 |
| Agastache breviflora | (A.Gray) Epling | Lamiaceae | 6 |
| Agave toumeyana | Trel. | Asparagaceae | 6 |
| Allium atrorubens | S.Watson | Amaryllidaceae | 6 |
| Allium parishii | S.Watson | Amaryllidaceae | 6 |
| Astragalus argophyllus | Nutt. | Fabaceae | 6 |
| Astragalus geyeri | A.Gray | Fabaceae | 6 |
| Bacopa eisenii | (Kellogg) Pennell | Plantaginaceae | 6 |
| Bacopa rotundifolia | (Michx.) Wettst. | Plantaginaceae | 6 |
| Bouteloua diversispicula | Columbus | Poaceae | 6 |
| Buchnera obliqua | Benth. | Orobanchaceae | 6 |
| Calystegia macounii | (Greene) Brummitt | Convolvulaceae | 6 |
| Carex oreocharis | Holm | Cyperaceae | 6 |
| Castilleja lineata | Greene | Orobanchaceae | 6 |
| Castilleja nervata | Eastw. | Orobanchaceae | 6 |
| Choisya arizonica | Standl. | Rutaceae | 6 |
| Cyperus amabilis | Vahl | Cyperaceae | 6 |
| Dermatophyllum arizonicum | (S.Watson) Vincent | Fabaceae | 6 |
| Descurainia adenophora | (Wooton & Standl.) O.E.Schulz | Brassicaceae | 6 |
| Echinocactus horizonthalonius | Lem. | Cactaceae | 6 |
| Ericameria watsonii | (A.Gray) G.L.Nesom | Asteraceae | 6 |
| Eriogonum zionis | J.T.Howell | Polygonaceae | 6 |
| Euphrosyne acerosa | (Nutt.) Panero | Asteraceae | 6 |
| Euploca fruticosa | (L.) J.I.M.Melo & Semir | Heliotropiaceae | 6 |
| Festuca thurberi | Vasey | Poaceae | 6 |
| Flaveria campestris | J.R.Johnst. | Asteraceae | 6 |
| Gayophytum diffusum | Torr. & A.Gray | Onagraceae | 6 |
| Gnaphalium exilifolium | A.Nelson | Asteraceae | 6 |
| Graptopetalum rusbyi | Rose | Crassulaceae | 6 |
| Grindelia arizonica | A.Gray | Asteraceae | 6 |
| Hackelia besseyi | (Rydb.) J.L.Gentry | Boraginaceae | 6 |
| Hymenothrix loomisii | S.F.Blake | Asteraceae | 6 |
| Hypoxis mexicana | Schult. & Schult.f. | Hypoxidaceae | 6 |
| Imperata brevifolia | Vasey | Poaceae | 6 |
| Indigofera sphaerocarpa | A.Gray | Fabaceae | 6 |
| Juncus chlorocephalus | Engelm. | Juncaceae | 6 |
| Lygodesmia grandiflora | (Nutt.) Torr. & A.Gray | Asteraceae | 6 |
| Marsilea mollis | B.L.Rob. & Fernald | Marsileaceae | 6 |
| Mentzelia integra | (M.E.Jones) Tidestr. | Loasaceae | 6 |
| Microchloa kunthii | Desv. | Poaceae | 6 |
| Navarretia saximontana | S.C.Spencer | Polemoniaceae | 6 |
| Pelecyphora sneedii | (Britton & Rose) D.Aquino & Dan.Sánchez | Cactaceae | 6 |
| Phacelia lemmonii | A.Gray | Hydrophyllaceae | 6 |
| Phalaris angusta | Nees ex Trin. | Poaceae | 6 |
| Plantago argyrea | E.Morris | Plantaginaceae | 6 |
| Polygonum ramosissimum | Michx. | Polygonaceae | 6 |
| Seymeria bipinnatisecta | Seem. | Orobanchaceae | 6 |
| Thelypodiopsis elegans | (M.E.Jones) Rydb. | Brassicaceae | 6 |
| Woodsia plummerae | Lemmon | Woodsiaceae | 6 |
| Apacheria chiricahuensis | C.T.Mason | Crossosomataceae | 5 |
| Argemone gracilenta | Greene | Papaveraceae | 5 |
| Aristida havardii | Vasey | Poaceae | 5 |
| Aristida schiedeana | Trin. & Rupr. | Poaceae | 5 |
| Astragalus holmgreniorum | Barneby | Fabaceae | 5 |
| Astragalus rusbyi | Greene | Fabaceae | 5 |
| Astragalus tetrapterus | A.Gray | Fabaceae | 5 |
| Astragalus toanus | M.E.Jones | Fabaceae | 5 |
| Bletia parva | Sosa & M.W.Chase | Orchidaceae | 5 |
| Bothriochloa springfieldii | (Gould) Parodi | Poaceae | 5 |
| Bromus orcuttianus | Vasey | Poaceae | 5 |
| Canavalia ensiformis | (L.) DC. | Fabaceae | 5 |
| Carex jonesii | L.H.Bailey | Cyperaceae | 5 |
| Carex ultra | L.H.Bailey | Cyperaceae | 5 |
| Chenopodium neomexicanum | Standl. | Chenopodiaceae | 5 |
| Chrysothamnus stylosus | (Eastw.) Urbatsch, R.P.Roberts & Neubig | Asteraceae | 5 |
| Chylismia multijuga | (S.Watson) Small | Onagraceae | 5 |
| Crusea wrightii | A.Gray | Rubiaceae | 5 |
| Cryptantha muricata | (Hook. & Arn.) A.Nelson & J.F.Macbr. | Boraginaceae | 5 |
| Cuscuta chinensis | Lam. | Convolvulaceae | 5 |
| Cuscuta salina | Engelm. | Convolvulaceae | 5 |
| Cyperus mutisii | (Kunth) Andersson | Cyperaceae | 5 |
| Descurainia obtusa | (Greene) O.E.Schulz | Brassicaceae | 5 |
| Digitaria pubiflora | (Vasey) Wipff | Poaceae | 5 |
| Echinocereus rigidissimus | (Engelm.) Rose | Cactaceae | 5 |
| Eleocharis flavescens | (Poir.) Urb. | Cyperaceae | 5 |
| Elymus arizonicus | (Scribn. & J.G.Sm.) Gould | Poaceae | 5 |
| Eriocoma lemmonii | (Vasey) Romasch. | Poaceae | 5 |
| Euphorbia bilobata | Engelm. | Euphorbiaceae | 5 |
| Gayophytum racemosum | Torr. & A.Gray | Onagraceae | 5 |
| Gentiana fremontii | Torr. | Gentianaceae | 5 |
| Gilia modocensis | Eastw. | Polemoniaceae | 5 |
| Gutierrezia wrightii | A.Gray | Asteraceae | 5 |
| Heterotheca marginata | Semple | Asteraceae | 5 |
| Malvastrum bicuspidatum | (S.Watson) Rose | Malvaceae | 5 |
| Mostacillastrum purpusii | (Brandegee) Al-Shehbaz | Brassicaceae | 5 |
| Muhlenbergia andina | (Nutt.) Hitchc. | Poaceae | 5 |
| Muhlenbergia dubia | E.Fourn. | Poaceae | 5 |
| Nemacladus longiflorus | A.Gray | Campanulaceae | 5 |
| Notholaena grayi | Davenp. | Pteridaceae | 5 |
| Notholaena neglecta | Maxon | Pteridaceae | 5 |
| Oenothera neomexicana | (Small) Munz | Onagraceae | 5 |
| Packera quercetorum | (Greene) C.Jeffrey | Asteraceae | 5 |
| Parthenice mollis | A.Gray | Asteraceae | 5 |
| Pediomelum mephiticum | (S.Watson) Rydb. | Fabaceae | 5 |
| Penstemon stenophyllus | A.Gray | Plantaginaceae | 5 |
| Perityle gracilis | (M.E.Jones) Rydb. | Asteraceae | 5 |
| Plectocephalus rothrockii | (Greenm.) D.J.N.Hind | Asteraceae | 5 |
| Polygonum polygaloides | Meisn. | Polygonaceae | 5 |
| Psilactis brevilingulata | Sch.Bip. ex Hemsl. | Asteraceae | 5 |
| Schiedeella arizonica | P.M.Br. | Orchidaceae | 5 |
| Silene thurberi | S.Watson | Caryophyllaceae | 5 |
| Solanum pinnatisectum | Dunal | Solanaceae | 5 |
| Sphaeralcea orcuttii | Rose | Malvaceae | 5 |
| Stenotis greenei | (A.Gray) Terrell & H.Rob. | Rubiaceae | 5 |
| Stevia micrantha | Lag. | Asteraceae | 5 |
| Thelypodiopsis ambigua | (S.Watson) Al-Shehbaz | Brassicaceae | 5 |
| Adenophyllum porophyllum | (Cav.) Hemsl. | Asteraceae | 4 |
| Allium bigelovii | S.Watson | Amaryllidaceae | 4 |
| Astragalus albulus | Wooton & Standl. | Fabaceae | 4 |
| Astragalus coltonii | M.E.Jones | Fabaceae | 4 |
| Astragalus sesquiflorus | S.Watson | Fabaceae | 4 |
| Astragalus wingatanus | S.Watson | Fabaceae | 4 |
| Bouteloua simplex | Lag. | Poaceae | 4 |
| Brickellia lemmonii | A.Gray | Asteraceae | 4 |
| Brickellia venosa | B.L.Rob. | Asteraceae | 4 |
| Cochlospermum palmatifidum | (DC.) Byng & Christenh. | Bixaceae | 4 |
| Cynanchum ligulatum | (Benth.) Woodson | Apocynaceae | 4 |
| Cyperus dipsaceus | Liebm. | Cyperaceae | 4 |
| Cyperus hemidrummondii | Goetgh. | Cyperaceae | 4 |
| Dimorphocarpa pinnatifida | Rollins | Brassicaceae | 4 |
| Eremogone aberrans | (M.E.Jones) Ikonn. | Caryophyllaceae | 4 |
| Erigeron canus | A.Gray | Asteraceae | 4 |
| Erigeron eximius | Greene | Asteraceae | 4 |
| Erigeron grandiflorus | Hook. | Asteraceae | 4 |
| Eriogonum divaricatum | Hook. | Polygonaceae | 4 |
| Eriogonum pulchrum | Eastw. | Polygonaceae | 4 |
| Eucnide rupestris | (Baill.) H.J.Thomps. & W.R.Ernst | Loasaceae | 4 |
| Gonolobus arizonicus | (A.Gray) Woodson | Apocynaceae | 4 |
| Graptopetalum bartramii | Rose | Crassulaceae | 4 |
| Halenia rothrockii | A.Gray | Gentianaceae | 4 |
| Heteranthera rotundifolia | (Kunth) Griseb. | Pontederiaceae | 4 |
| Juncus laccatus | P.F.Zika | Juncaceae | 4 |
| Lysiloma watsonii | Rose | Fabaceae | 4 |
| Muhlenbergia ramulosa | (Kunth) Swallen | Poaceae | 4 |
| Muhlenbergia straminea | Hitchc. | Poaceae | 4 |
| Myriopteris pringlei | (Davenp.) Grusz & Windham | Pteridaceae | 4 |
| Oenothera longissima | Rydb. | Onagraceae | 4 |
| Oreocarya bakeri | Greene | Boraginaceae | 4 |
| Oreocarya capitata | Eastw. | Boraginaceae | 4 |
| Packera hartiana | (A.Heller) W.A.Weber & Á.Löve | Asteraceae | 4 |
| Penstemon lentus | Pennell | Plantaginaceae | 4 |
| Potentilla subviscosa | Greene | Rosaceae | 4 |
| Sairocarpus watsonii | (Vasey & Rose) D.A.Sutton | Plantaginaceae | 4 |
| Sclerocactus whipplei | (Engelm. & J.M.Bigelow) Britton & Rose | Cactaceae | 4 |
| Sisyrinchium arizonicum | Rothr. | Iridaceae | 4 |
| Stylocline intertexta | Morefield | Asteraceae | 4 |
| Symphyotrichum welshii | (Cronquist) G.L.Nesom | Asteraceae | 4 |
| Townsendia jonesii | (Beaman) Reveal | Asteraceae | 4 |
| Agastache micrantha | (A.Gray) Wooton & Standl. | Lamiaceae | 3 |
| Amaranthus crassipes | Schltdl. | Amaranthaceae | 3 |
| Artemisia franserioides | Greene | Asteraceae | 3 |
| Asclepias elata | Benth. | Apocynaceae | 3 |
| Asclepias macrotis | Torr. | Apocynaceae | 3 |
| Astragalus egglestonii | (Rydb.) Kearney & Peebles | Fabaceae | 3 |
| Astragalus insularis | Kellogg | Fabaceae | 3 |
| Berberis harrisoniana | Kearney & Peebles | Berberidaceae | 3 |
| Boechera crandallii | (B.L.Rob.) W.A.Weber | Brassicaceae | 3 |
| Bouteloua erecta | (Vasey & Hack.) Columbus | Poaceae | 3 |
| Chenopodium desiccatum | A.Nelson | Chenopodiaceae | 3 |
| Cochemiea wrightii | (Engelm. & J.M.Bigelow) Doweld | Cactaceae | 3 |
| Coenoemersa limosa | (Lindl.) R.González & Lizb.Hern. | Orchidaceae | 3 |
| Cryptantha decipiens | (M.E.Jones) A.Heller | Boraginaceae | 3 |
| Cuscuta legitima | Costea & Stefanović | Convolvulaceae | 3 |
| Dalea lumholtzii | C.B.Rob. & Fernald | Fabaceae | 3 |
| Draba crassifolia | Graham | Brassicaceae | 3 |
| Eremothera gouldii | (P.H.Raven) W.L.Wagner & Hoch | Onagraceae | 3 |
| Erigeron lobatus | A.Nelson | Asteraceae | 3 |
| Erigeron versicolor | (Greenm.) G.L.Nesom | Asteraceae | 3 |
| Eriocoma robusta | (Vasey) Romasch. | Poaceae | 3 |
| Erysimum inconspicuum | (S.Watson) MacMill. | Brassicaceae | 3 |
| Euphorbia alta | Norton | Euphorbiaceae | 3 |
| Festuca minutiflora | Rydb. | Poaceae | 3 |
| Fraxinus gooddingii | Little | Oleaceae | 3 |
| Galium uncinulatum | DC. | Rubiaceae | 3 |
| Gentianella amarella | (L.) Börner | Gentianaceae | 3 |
| Glyptopleura setulosa | A.Gray | Asteraceae | 3 |
| Harpagonella arizonica | (I.M.Johnst.) Guilliams & B.G.Baldwin | Boraginaceae | 3 |
| Helenium arizonicum | S.F.Blake | Asteraceae | 3 |
| Ipomoea tenuiloba | Torr. | Convolvulaceae | 3 |
| Koanophyllon palmeri | (A.Gray) R.M.King & H.Rob. | Asteraceae | 3 |
| Lepidium eastwoodiae | Wooton | Brassicaceae | 3 |
| Leucosyris parviflora | (A.Gray) Pruski & R.L.Hartm. | Asteraceae | 3 |
| Mandevilla brachysiphon | (Torr.) Pichon | Apocynaceae | 3 |
| Mentzelia isolata | Gentry | Loasaceae | 3 |
| Mitracarpus breviflorus | A.Gray | Rubiaceae | 3 |
| Monoptilon bellidiforme | Torr. & A.Gray | Asteraceae | 3 |
| Muhlenbergia appressa | Goodd. | Poaceae | 3 |
| Muhlenbergia pauciflora | Buckley | Poaceae | 3 |
| Muhlenbergia repens | (J.Presl) Hitchc. | Poaceae | 3 |
| Oenothera havardii | S.Watson | Onagraceae | 3 |
| Opuntia diploursina | Stock, N.Hussey & Beckstrom | Cactaceae | 3 |
| Panicum urvilleanum | Kunth | Poaceae | 3 |
| Pectis imberbis | A.Gray | Asteraceae | 3 |
| Pectis longipes | A.Gray | Asteraceae | 3 |
| Phacelia bakeri | (Brand) J.F.Macbr. | Hydrophyllaceae | 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 |
| Phlox viscida | E.E.Nelson | Polemoniaceae | 3 |
| Physaria newberryi | A.Gray | Brassicaceae | 3 |
| Polemonium apachianum | J.P.Rose | Polemoniaceae | 3 |
| Potentilla jepsonii | Ertter | Rosaceae | 3 |
| Pseudoeriocoma eminens | (Cav.) Romasch. | Poaceae | 3 |
| Quercus ajoensis | C.H.Mull. | Fagaceae | 3 |
| Ranunculus cupulatus | (S.Watson) Christenh. & Byng | Ranunculaceae | 3 |
| Salvia amissa | Epling | Lamiaceae | 3 |
| Sambucus mexicana | C.Presl ex DC. | Viburnaceae | 3 |
| Tamayorkis porphyrea | (Ridl.) Salazar & Soto Arenas | Orchidaceae | 3 |
| Trichogalium microphyllum | (A.Gray) Kadereit & Schneew. | Rubiaceae | 3 |
| Vauquelinia californica | (Torr.) Sarg. | Rosaceae | 3 |
| Viola umbraticola | Kunth | Violaceae | 3 |
| Woodsia cochisensis | Windham | Woodsiaceae | 3 |
Abdra brachycarpa
Abies concolorwhite fir
Abies lasiocarpaAlpine Fir
Abronia angustifoliapurple sand verbena
Abronia carneawinged sandpuffs
Abronia ellipticafragrant white sand verbena
Abronia fragranssnowball sand verbena
Abronia nanadwarf sand verbena
Abronia villosadesert sand verbena
Abutilon abutiloidesshrubby Indian mallow
Abutilon incanumHoary Indian-mallow
Abutilon malacumyellow Indian mallow
Abutilon mollicomumSonoran Indian mallow
Abutilon palmeriPalmer's Indian mallow
Abutilon parishiiParish's Indian mallow
Abutilon parvulumdwarf Indian mallow
Abutilon reventumyellowflower Indian mallow
Acaciella angustissimaprairie acacia
Acalypha californicaCalifornia copperleaf
Acalypha mexicanaMexican copperleaf
Acalypha neomexicanaNew Mexico copperleaf
Acalypha persimilispineland threeseed mercury
Acalypha phleoidesshrubby copperleaf
Acamptopappus sphaerocephalusrayless goldenhead
Acer glabrumRocky Mountain maple
Acer negundobox elder
Acer saccharumsugar maple
Achillea millefoliumcommon yarrow
Achyronychia cooperionyxflower
Acleisanthes chenopodioidesgoosefoot moonpod
Acleisanthes longifloraangel's trumpets
Acleisanthes nevadensisdesert moonpod
Acmispon americanusSpanish clover
Acmispon brachycarpusfoothill deervetch
Acmispon glaberdeerweed
Acmispon maritimuscoastal bird's-foot trefoil
Acmispon mearnsiiMearns' bird's-foot trefoil
Acmispon micranthusDesert Deervetch
Acmispon neomexicanusGreene's bird's-foot trefoil
Acmispon oroboides
Acmispon rigidusBroom Lotus
Acmispon utahensisUtah bird's-foot trefoil
Acmispon wrightiiWright's deervetch
Aconitum columbianumColumbian Monkshood
Acourtia nanadwarf desertpeony
Acourtia wrightiibrownfoot
Actaea rubrared baneberry
Adenophyllum cooperiCooper's dogweed
