| Abies concolor | (Gordon) Lindl. ex Hildebr. | Pinaceae | 8 |
| Abies lasiocarpa | (Hook.) Nutt. | Pinaceae | 8 |
| Abronia angustifolia | Greene | Nyctaginaceae | 8 |
| Abronia bigelovii | Heimerl | Nyctaginaceae | 8 |
| Abronia carnea | Greene | Nyctaginaceae | 8 |
| Abronia elliptica | A.Nelson | Nyctaginaceae | 8 |
| Abronia fragrans | Nutt. ex Hook. | Nyctaginaceae | 8 |
| Abronia micrantha | Torr. | Nyctaginaceae | 8 |
| Abronia nealleyi | Standl. | Nyctaginaceae | 8 |
| Abutilon fruticosum | Guill. & Perr. | Malvaceae | 8 |
| Abutilon incanum | (Link) Sweet | Malvaceae | 8 |
| Abutilon malacum | S.Watson | Malvaceae | 8 |
| Abutilon mollicomum | (Willd.) Sweet | Malvaceae | 8 |
| Abutilon parvulum | A.Gray | Malvaceae | 8 |
| Abutilon wrightii | A.Gray | Malvaceae | 8 |
| Acaciella angustissima | (Mill.) Britton & Rose | Fabaceae | 8 |
| Acalypha neomexicana | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha persimilis | Müll.Arg. | Euphorbiaceae | 8 |
| Acalypha phleoides | Cav. | Euphorbiaceae | 8 |
| Acer glabrum | Torr. | Sapindaceae | 8 |
| Acer negundo | L. | Sapindaceae | 8 |
| Acer rubrum | L. | Sapindaceae | 8 |
| Acer saccharum | Marshall | Sapindaceae | 8 |
| Achillea millefolium | L. | Asteraceae | 8 |
| Acleisanthes chenopodioides | (A.Gray) R.A.Levin | Nyctaginaceae | 8 |
| Acleisanthes diffusa | (A.Gray) R.A.Levin | Nyctaginaceae | 8 |
| Acleisanthes lanceolata | (Wooton) R.A.Levin | Nyctaginaceae | 8 |
| Acleisanthes longiflora | A.Gray | Nyctaginaceae | 8 |
| Acmispon americanus | (Nutt.) Rydb. | Fabaceae | 8 |
| Acmispon brachycarpus | (Benth.) D.D.Sokoloff | Fabaceae | 8 |
| Acmispon neomexicanus | (Greene) Brouillet | Fabaceae | 8 |
| Acmispon oroboides | (Kunth) 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 wrightii | A.Gray | Asteraceae | 8 |
| Adiantum capillus-veneris | L. | Pteridaceae | 8 |
| Adolphia infesta | (Kunth) Meisn. | Rhamnaceae | 8 |
| Adoxa moschatellina | L. | Viburnaceae | 8 |
| Agalinis tenuifolia | (Vahl) Raf. | Orobanchaceae | 8 |
| Agastache pallidiflora | (A.Heller) Rydb. | Lamiaceae | 8 |
| Agave lechuguilla | Torr. | Asparagaceae | 8 |
| Agave palmeri | Engelm. | Asparagaceae | 8 |
| Agave parryi | Engelm. | Asparagaceae | 8 |
| Agave schottii | Engelm. | Asparagaceae | 8 |
| Ageratina herbacea | (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 |
| Agrimonia gryposepala | Wallr. | Rosaceae | 8 |
| Agrimonia parviflora | Aiton | Rosaceae | 8 |
| Agrimonia striata | Michx. | Rosaceae | 8 |
| Agrostis scabra | Willd. | Poaceae | 8 |
| Aldama cordifolia | (A.Gray) E.E.Schill. & Panero | Asteraceae | 8 |
| Aliciella haydenii | (A.Gray) J.M.Porter | Polemoniaceae | 8 |
| Aliciella leptomeria | (A.Gray) J.M.Porter | Polemoniaceae | 8 |
| Aliciella pinnatifida | (Nutt. ex A.Gray) 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 subcordatum | Raf. | 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 brevistylum | S.Watson | Amaryllidaceae | 8 |
| Allium cernuum | Roth | Amaryllidaceae | 8 |
| Allium drummondii | Regel | Amaryllidaceae | 8 |
| Allium geyeri | S.Watson | Amaryllidaceae | 8 |
| Allium longifolium | (Kunth) Spreng. | Amaryllidaceae | 8 |
| Allium macropetalum | Rydb. | Amaryllidaceae | 8 |
| Allium rhizomatum | Wooton & Standl. | Amaryllidaceae | 8 |
| Allium textile | A.Nelson & J.F.Macbr. | Amaryllidaceae | 8 |
| Allowissadula holosericea | (Scheele) D.M.Bates | Malvaceae | 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 polygonoides | L. | Amaranthaceae | 8 |
| Amaranthus powellii | S.Watson | Amaranthaceae | 8 |
| Amaranthus watsonii | Standl. | Amaranthaceae | 8 |
| Ambrosia acanthicarpa | Hook. | Asteraceae | 8 |
| Ambrosia artemisiifolia | L. | Asteraceae | 8 |
| Ambrosia confertiflora | DC. | Asteraceae | 8 |
| Ambrosia grayi | (A.Nelson) Shinners | 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 |
| Ammoselinum popei | Torr. & A.Gray | Apiaceae | 8 |
| Amorpha californica | Nutt. | Fabaceae | 8 |
| Amorpha canescens | Pursh | Fabaceae | 8 |
| Amorpha fruticosa | L. | Fabaceae | 8 |
| Amorpha nana | Nutt. | Fabaceae | 8 |
| Amsinckia menziesii | (Lehm.) A.Nelson & J.F.Macbr. | Boraginaceae | 8 |
| Amsinckia tessellata | A.Gray | Boraginaceae | 8 |
| Amsonia longiflora | Torr. | Apocynaceae | 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 lehmanniana | Spreng. | Primulaceae | 8 |
| Androsace occidentalis | Pursh | Primulaceae | 8 |
| Androsace septentrionalis | L. | Primulaceae | 8 |
| Androstephium breviflorum | S.Watson | Asparagaceae | 8 |
| Anemonastrum canadense | (L.) Mosyakin | Ranunculaceae | 8 |
| Anemone cylindrica | A.Gray | Ranunculaceae | 8 |
| Anemone multifida | Poir. | Ranunculaceae | 8 |
| Anemone okennonii | Keener & B.E.Dutton | Ranunculaceae | 8 |
| Anemone tuberosa | Rydb. | Ranunculaceae | 8 |
| Anemopsis californica | (Nutt.) Hook. & Arn. | Saururaceae | 8 |
| Angelica ampla | A.Nelson | Apiaceae | 8 |
| Angelica grayi | (J.M.Coult. & Rose) J.M.Coult. & Rose | Apiaceae | 8 |
| Angelica pinnata | S.Watson | Apiaceae | 8 |
| Anisacanthus thurberi | (Torr.) A.Gray | Acanthaceae | 8 |
| Anoda cristata | (L.) Schltdl. | Malvaceae | 8 |
| Anoda lanceolata | Hook. & Arn. | Malvaceae | 8 |
| Anoda pentaschista | A.Gray | Malvaceae | 8 |
| Antennaria dimorpha | Torr. & A.Gray | Asteraceae | 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 |
| 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 |
| Aralia bicrenata | Wooton & Standl. | Araliaceae | 8 |
| Arbutus arizonica | (A.Gray) Sarg. | Ericaceae | 8 |
| Arbutus xalapensis | Kunth | 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 pungens | Kunth | Ericaceae | 8 |
| Arctostaphylos uva-ursi | (L.) Spreng. | Ericaceae | 8 |
| Arenaria benthamii | Fenzl ex Torr. & A.Gray | Caryophyllaceae | 8 |
| Arenaria lanuginosa | (Michx.) Rohrb. | Caryophyllaceae | 8 |
| Argemone hispida | A.Gray | Papaveraceae | 8 |
| Argemone pleiacantha | Greene | Papaveraceae | 8 |
| Argemone polyanthemos | (Fedde) Ownbey | Papaveraceae | 8 |
| Argemone squarrosa | Greene | Papaveraceae | 8 |
| Argentina anserina | (L.) Rydb. | Rosaceae | 8 |
| Argyrochosma fendleri | (Kunze) Windham | Pteridaceae | 8 |
| Argyrochosma limitanea | (Maxon) Windham | Pteridaceae | 8 |
| Argyrochosma microphylla | (Kuhn) Windham | Pteridaceae | 8 |
| Aristida adscensionis | L. | Poaceae | 8 |
| Aristida arizonica | Vasey | Poaceae | 8 |
| Aristida divaricata | Humb. & Bonpl. ex Willd. | Poaceae | 8 |
| Aristida 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 |
| Aristolochia wrightii | Seem. | 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 laciniata | C.B.Clarke | Asteraceae | 8 |
| Artemisia ludoviciana | Nutt. | Asteraceae | 8 |
| Artemisia nova | A.Nelson | Asteraceae | 8 |
| Artemisia pygmaea | A.Gray | Asteraceae | 8 |
| Artemisia scopulorum | A.Gray | Asteraceae | 8 |
| Artemisia tridentata | Nutt. | Asteraceae | 8 |
| Asclepias arenaria | Torr. | Apocynaceae | 8 |
| Asclepias asperula | (Decne.) Woodson | Apocynaceae | 8 |
| Asclepias brachystephana | Engelm. ex Torr. | Apocynaceae | 8 |
| Asclepias engelmanniana | Woodson | 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 linaria | Cav. | Apocynaceae | 8 |
| Asclepias nummularia | Torr. | Apocynaceae | 8 |
| Asclepias nyctaginifolia | A.Gray | Apocynaceae | 8 |
| Asclepias oenotheroides | Schltdl. & Cham. | Apocynaceae | 8 |
| Asclepias pumila | (A.Gray) Vail | Apocynaceae | 8 |
| Asclepias rusbyi | (Vail) Woodson | Apocynaceae | 8 |
| Asclepias speciosa | Torr. | Apocynaceae | 8 |
| Asclepias subverticillata | (A.Gray) Vail | Apocynaceae | 8 |
| Asclepias tuberosa | L. | Apocynaceae | 8 |
| Asclepias viridiflora | Raf. | Apocynaceae | 8 |
| Aspicarpa hirtella | Rich. | Malpighiaceae | 8 |
| Asplenium platyneuron | (L.) Britton, Sterns & Poggenb. | Aspleniaceae | 8 |
| Asplenium resiliens | Kunze | Aspleniaceae | 8 |
| Asplenium scolopendrium | L. | Aspleniaceae | 8 |
| Asplenium septentrionale | (L.) Hoffm. | Aspleniaceae | 8 |
| Asplenium trichomanes | L. | Aspleniaceae | 8 |
| Astragalus agrestis | Douglas ex G.Don | Fabaceae | 8 |
| Astragalus allochrous | A.Gray | Fabaceae | 8 |
| Astragalus alpinus | L. | Fabaceae | 8 |
| Astragalus amphioxys | A.Gray | Fabaceae | 8 |
| Astragalus bisulcatus | (Hook.) A.Gray | Fabaceae | 8 |
| Astragalus bodinii | E.Sheld. | Fabaceae | 8 |
| Astragalus brandegeei | Porter | Fabaceae | 8 |
| Astragalus calycosus | Torr. ex S.Watson | Fabaceae | 8 |
| Astragalus canadensis | L. | Fabaceae | 8 |
| Astragalus ceramicus | E.Sheld. | Fabaceae | 8 |
| Astragalus cobrensis | A.Gray | Fabaceae | 8 |
| Astragalus crassicarpus | Nutt. | Fabaceae | 8 |
| Astragalus desperatus | M.E.Jones | Fabaceae | 8 |
| Astragalus drummondii | Douglas ex Hook. | 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 gracilis | Nutt. | Fabaceae | 8 |
| Astragalus gypsodes | Barneby | Fabaceae | 8 |
| Astragalus hallii | A.Gray | Fabaceae | 8 |
| Astragalus humistratus | A.Gray | Fabaceae | 8 |
| Astragalus kentrophyta | A.Gray | Fabaceae | 8 |
| Astragalus laxmannii | Jacq. | Fabaceae | 8 |
| Astragalus lentiginosus | Douglas ex Hook. | Fabaceae | 8 |
| Astragalus lonchocarpus | Torr. | Fabaceae | 8 |
| Astragalus lotiflorus | Hook. | Fabaceae | 8 |
| Astragalus miser | Douglas ex Hook. | Fabaceae | 8 |
| Astragalus missouriensis | Nutt. | Fabaceae | 8 |
| Astragalus mollissimus | Torr. | Fabaceae | 8 |
| Astragalus multiflorus | (Pursh) A.Gray | Fabaceae | 8 |
| Astragalus newberryi | A.Gray | Fabaceae | 8 |
| Astragalus nothoxys | A.Gray | Fabaceae | 8 |
| Astragalus nuttallianus | DC. | Fabaceae | 8 |
| Astragalus praelongus | E.Sheld. | Fabaceae | 8 |
| Astragalus racemosus | Pursh | Fabaceae | 8 |
| Astragalus robbinsii | (Oakes) A.Gray | Fabaceae | 8 |
| Astragalus sabulonum | A.Gray | Fabaceae | 8 |
| Astragalus scopulorum | Porter | Fabaceae | 8 |
| Astragalus sericoleucus | A.Gray | Fabaceae | 8 |
| Astragalus shortianus | Nutt. | 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 |
| 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 corrugata | S.Watson | Chenopodiaceae | 8 |
| Atriplex elegans | (Moq.) D.Dietr. | Chenopodiaceae | 8 |
| Atriplex obovata | Moq. | Chenopodiaceae | 8 |
| Atriplex saccaria | S.Watson | Chenopodiaceae | 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 pilularis | DC. | Asteraceae | 8 |
| Baccharis pteronioides | DC. | Asteraceae | 8 |
| Baccharis salicifolia | (Ruiz & Pav.) Pers. | Asteraceae | 8 |
| Baccharis salicina | Torr. & A.Gray | Asteraceae | 8 |
| Baccharis sarothroides | A.Gray | Asteraceae | 8 |
| Baccharis texana | A.Gray | Asteraceae | 8 |
| Baccharis thesioides | Kunth | Asteraceae | 8 |
| Baccharis wrightii | A.Gray | Asteraceae | 8 |
| Barbarea orthoceras | Ledeb. | Brassicaceae | 8 |
| Barkleyanthus salicifolius | (Kunth) H.Rob. & Brettell | Asteraceae | 8 |
| Bartlettia scaposa | A.Gray | Asteraceae | 8 |
| Bebbia juncea | Greene | Asteraceae | 8 |
| Beckmannia syzigachne | (Steud.) Fernald | Poaceae | 8 |
| Berberis fendleri | A.Gray | Berberidaceae | 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 obovata | I.M.Johnst. | Euphorbiaceae | 8 |
| Berula erecta | (Huds.) Coville | Apiaceae | 8 |
| Betula glandulosa | Michx. | Betulaceae | 8 |
| Betula occidentalis | Hook. | Betulaceae | 8 |
| Bidens alba | DC. | 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 polylepis | S.F.Blake | Asteraceae | 8 |
| Bidens tenuisecta | A.Gray | Asteraceae | 8 |
| Bidens tripartita | L. | Asteraceae | 8 |
| Bletia arizonica | (S.Watson) Sosa & M.W.Chase | Orchidaceae | 8 |
| Bletia nitida | (L.O.Williams) Sosa & M.W.Chase | Orchidaceae | 8 |
| Bletia spicata | (Walter) 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 perennans | (S.Watson) W.A.Weber | Brassicaceae | 8 |
| Boechera quadrangulensis | Windham & Allphin | 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 linearifolia | A.Gray | Nyctaginaceae | 8 |
| Boerhavia purpurascens | A.Gray | Nyctaginaceae | 8 |
| Boerhavia scandens | L. | Nyctaginaceae | 8 |
| Boerhavia triquetra | S.Watson | Nyctaginaceae | 8 |
| Boerhavia wrightii | A.Gray | Nyctaginaceae | 8 |
| Bolboschoenus 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 lanceolatum | (Gmel.) Ångstr. | Ophioglossaceae | 8 |
| Botrypus virginianus | (L.) Michx. | Ophioglossaceae | 8 |
| Bouchea linifolia | A.Gray ex Torr. | Verbenaceae | 8 |
| Bouteloua aristidoides | (Kunth) Griseb. | Poaceae | 8 |
| Bouteloua barbata | Lag. | 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 rigidiseta | (Steud.) Hitchc. | Poaceae | 8 |
| Bouteloua trifida | Thurb. ex S.Watson | Poaceae | 8 |
| Bouteloua warnockii | Gould & Kapadia | Poaceae | 8 |
| Bouvardia ternifolia | (Cav.) Schltdl. | Rubiaceae | 8 |
| Bowlesia incana | Ruiz & Pav. | Apiaceae | 8 |
| Brickellia baccharidea | A.Gray | Asteraceae | 8 |
| Brickellia betonicifolia | A.Gray | Asteraceae | 8 |
| Brickellia coulteri | A.Gray | Asteraceae | 8 |
| Brickellia grandiflora | Nutt. | Asteraceae | 8 |
| Brickellia laciniata | A.Gray | Asteraceae | 8 |
| Brickellia leptophylla | (Scheele) Shinn. | 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 anomalus | Rupr. ex E.Fourn. | Poaceae | 8 |
| Bromus carinatus | Hook. & Arn. | Poaceae | 8 |
| Bromus ciliatus | L. | Poaceae | 8 |
| Bromus porteri | (Coult.) Nash | Poaceae | 8 |
| Bromus pumpellianus | Scribn. | Poaceae | 8 |
| Buddleja scordioides | Kunth | Scrophulariaceae | 8 |
| Bulbostylis capillaris | (L.) Kunth ex C.B.Clarke | Cyperaceae | 8 |
| Bupleurum americanum | J.M.Coult. & Rose | Apiaceae | 8 |
| Calamagrostis canadensis | (Michx.) P.Beauv. | Poaceae | 8 |
| Calamagrostis inexpansa | A.Gray | Poaceae | 8 |
| Calamagrostis purpurascens | R.Br. | Poaceae | 8 |
| Calandrinia ciliata | (Ruiz & Pav.) DC. | Montiaceae | 8 |
| Calliandra eriophylla | Benth. | Fabaceae | 8 |
| Calliandra humilis | Benth. | Fabaceae | 8 |
| Callirhoe alcaeoides | (Michx.) A.Gray | Malvaceae | 8 |
| Callirhoe involucrata | (Torr. & A.Gray) A.Gray | Malvaceae | 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 nuttallii | Torr. | Liliaceae | 8 |
| Caltha chionophila | Greene | Ranunculaceae | 8 |
| Calycoseris wrightii | A.Gray | Asteraceae | 8 |
| Calypso bulbosa | (L.) Oakes | Orchidaceae | 8 |
| Calystegia sepium | (L.) R.Br. | Convolvulaceae | 8 |
| Camissonia parvula | (Nutt. ex Torr. & A.Gray) P.H.Raven | Onagraceae | 8 |
| Campanula parryi | A.Gray | Campanulaceae | 8 |
| Campanula petiolata | A.DC. | Campanulaceae | 8 |
| Cardamine cordifolia | A.Gray | Brassicaceae | 8 |
| Cardamine pensylvanica | Muhl. ex Willd. | Brassicaceae | 8 |
| Carex alascana | Boeckeler | Cyperaceae | 8 |
| Carex amplifolia | Boott | Cyperaceae | 8 |
| Carex aquatilis | Wahlenb. | Cyperaceae | 8 |
| Carex atherodes | Spreng. | Cyperaceae | 8 |
| Carex athrostachya | Olney | Cyperaceae | 8 |
| Carex aurea | Nutt. | Cyperaceae | 8 |
| Carex aureolensis | Steud. | Cyperaceae | 8 |
| Carex bebbii | (L.H.Bailey) Olney ex Fernald | Cyperaceae | 8 |
| Carex bella | L.H.Bailey | Cyperaceae | 8 |
| Carex blanda | Dewey | Cyperaceae | 8 |
| Carex brevior | (Dewey) Mack. ex Lunell | Cyperaceae | 8 |
| Carex brunnescens | (Pers.) Poir. | Cyperaceae | 8 |
| Carex buxbaumii | Wahlenb. | Cyperaceae | 8 |
| Carex canescens | L. | Cyperaceae | 8 |
| Carex capillaris | L. | Cyperaceae | 8 |
| Carex capitata | Sol. | Cyperaceae | 8 |
| Carex chalciolepis | Holm | Cyperaceae | 8 |
| Carex deweyana | Schwein. | 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 frankii | Kunth | Cyperaceae | 8 |
| Carex garberi | Fernald | Cyperaceae | 8 |
| Carex gravida | L.H.Bailey | Cyperaceae | 8 |
| Carex hystericina | Muhl. ex Willd. | Cyperaceae | 8 |
| Carex illota | L.H.Bailey | Cyperaceae | 8 |
| Carex inops | L.H.Bailey | Cyperaceae | 8 |
| Carex interior | L.H.Bailey | Cyperaceae | 8 |
| Carex kelloggii | W.Boott | Cyperaceae | 8 |
| Carex lachenalii | Schkuhr | Cyperaceae | 8 |
| Carex leptalea | Wahlenb. | Cyperaceae | 8 |
| Carex limosa | L. | Cyperaceae | 8 |
| Carex luzulina | Olney | Cyperaceae | 8 |
| Carex macloviana | d'Urv. | Cyperaceae | 8 |
| Carex magellanica | Lam. | Cyperaceae | 8 |
| Carex microdonta | Torr. | Cyperaceae | 8 |
| Carex microglochin | Wahlenb. | Cyperaceae | 8 |
| Carex micropoda | C.A.Mey. | Cyperaceae | 8 |
| Carex microptera | Mack. | Cyperaceae | 8 |
| Carex myosuroides | Vill. | Cyperaceae | 8 |
| Carex nigricans | C.A.Mey. | Cyperaceae | 8 |
| Carex nova | L.H.Bailey | Cyperaceae | 8 |
| Carex occidentalis | L.H.Bailey | Cyperaceae | 8 |
| Carex pellita | Muhl. ex Willd. | Cyperaceae | 8 |
| Carex petasata | Dewey | Cyperaceae | 8 |
| Carex phaeocephala | Piper | Cyperaceae | 8 |
| Carex planostachys | Kunze | Cyperaceae | 8 |
| Carex praegracilis | W.Boott | Cyperaceae | 8 |
| Carex praticola | Rydb. | Cyperaceae | 8 |
| Carex rosea | Willd. | Cyperaceae | 8 |
| Carex rossii | Boott | Cyperaceae | 8 |
| Carex rupestris | All. | Cyperaceae | 8 |
| Carex scoparia | Schkuhr ex Willd. | Cyperaceae | 8 |
| Carex senta | Boott | Cyperaceae | 8 |
| Carex siccata | Dewey | Cyperaceae | 8 |
| Carex simpliciuscula | Wahlenb. | Cyperaceae | 8 |
| Carex sprengelii | Dewey ex Spreng. | Cyperaceae | 8 |
| Carex stevenii | (Holm) Kalela | Cyperaceae | 8 |
| Carex stipata | Muhl. ex Willd. | Cyperaceae | 8 |
| Carex stricta | Lam. | Cyperaceae | 8 |
| Carex subfusca | W.Boott | Cyperaceae | 8 |
| Carex tahoensis | Smiley | Cyperaceae | 8 |
| Carex tenera | Dewey | Cyperaceae | 8 |
| Carex tetrastachya | Scheele | Cyperaceae | 8 |
| Carex utriculata | Boott | Cyperaceae | 8 |
| Carex vallicola | Dewey | Cyperaceae | 8 |
| Carex vesicaria | L. | Cyperaceae | 8 |
| Carex vulpinoidea | Michx. | Cyperaceae | 8 |
| Carlowrightia linearifolia | (Torr.) A.Gray | Acanthaceae | 8 |
| Carlowrightia texana | Henrickson & T.F.Daniel | Acanthaceae | 8 |
| Carminatia tenuiflora | DC. | Asteraceae | 8 |
| Carphochaete bigelovii | A.Gray | Asteraceae | 8 |
| Castilleja chromosa | A.Nelson | Orobanchaceae | 8 |
| Castilleja exserta | (A.Heller) T.I.Chuang & Heckard | Orobanchaceae | 8 |
| Castilleja haydenii | (A.Gray) Cockerell | 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 nelsonii | Eastw. | Orobanchaceae | 8 |
| Castilleja occidentalis | Torr. | Orobanchaceae | 8 |
| Castilleja organorum | Standl. | Orobanchaceae | 8 |
| Castilleja patriotica | Fernald | Orobanchaceae | 8 |
| Castilleja rhexiifolia | Rydb. | Orobanchaceae | 8 |
| Castilleja scabrida | Eastw. | Orobanchaceae | 8 |
| Castilleja septentrionalis | Lindl. | Orobanchaceae | 8 |
| Castilleja sessiliflora | Pursh | Orobanchaceae | 8 |
| Castilleja tenuiflora | Benth. | Orobanchaceae | 8 |
| Castilleja wootonii | Standl. | Orobanchaceae | 8 |
| Catabrosa aquatica | (L.) P.Beauv. | Poaceae | 8 |
| Catalpa speciosa | (Warder) Engelm. | Bignoniaceae | 8 |
| Ceanothus fendleri | A.Gray | Rhamnaceae | 8 |
| Ceanothus herbaceus | Raf. | Rhamnaceae | 8 |
| Ceanothus pauciflorus | DC. | Rhamnaceae | 8 |
| Celtis laevigata | Willd. | Cannabaceae | 8 |
| Celtis occidentalis | L. | Cannabaceae | 8 |
| Celtis pallida | Torr. | Cannabaceae | 8 |
| Celtis reticulata | Torr. | Cannabaceae | 8 |
| Cenchrus echinatus | L. | Poaceae | 8 |
| Cenchrus spinifex | Cav. | Poaceae | 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 canadensis | L. | Fabaceae | 8 |
| Cercocarpus breviflorus | A.Gray | Rosaceae | 8 |
| Cercocarpus intricatus | S.Watson | 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 stevioides | Hook. & Arn. | Asteraceae | 8 |
| Chaetopappa ericoides | (Torr.) G.L.Nesom | Asteraceae | 8 |
| Chamaechaenactis scaposa | Rydb. | Asteraceae | 8 |
| Chamaecrista fasciculata | (Michx.) Greene | Fabaceae | 8 |
| Chamaecrista nictitans | (L.) Moench | Fabaceae | 8 |
| Chamaesaracha coniodes | (Moric. ex Dunal) Benth. & Hook.f. ex B.D.Jacks. | Solanaceae | 8 |
| Chamaesaracha coronopus | (Dunal) A.Gray | Solanaceae | 8 |
| Chamaesaracha pallida | Averett | Solanaceae | 8 |
| Chaptalia texana | Greene | Asteraceae | 8 |
| Chasmanthium latifolium | (Michx.) H.O.Yates | Poaceae | 8 |
| Chenopodium album | L. | Chenopodiaceae | 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 umbellata | (L.) W.P.C.Barton | Ericaceae | 8 |
| Chionophila jamesii | Benth. | Plantaginaceae | 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 |
| Chrysactinia mexicana | A.Gray | Asteraceae | 8 |
| Chrysothamnus depressus | Nutt. | Asteraceae | 8 |
| Chrysothamnus greenei | (A.Gray) Greene | Asteraceae | 8 |
| Chrysothamnus viscidiflorus | Nutt. | Asteraceae | 8 |
| Chthamalia biflora | (Raf.) Decne. | Apocynaceae | 8 |
| Chthamalia producta | (Torr.) L.O.Alvarado & E.B.Cortez | Apocynaceae | 8 |
| Chylismia claviformis | (Torr. & Frém.) A.Heller | Onagraceae | 8 |
| Chylismia scapoidea | (Torr. & A.Gray) Small | Onagraceae | 8 |
| Chylismia walkeri | A.Nelson | 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 eatonii | (A.Gray) B.L.Rob. | Asteraceae | 8 |
| Cirsium neomexicanum | A.Gray | Asteraceae | 8 |
| Cirsium ochrocentrum | A.Gray | Asteraceae | 8 |
| Cirsium parryi | Petr. | Asteraceae | 8 |
| Cirsium scariosum | Nutt. | Asteraceae | 8 |
| Cirsium texanum | Buckley | 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 |
| Claytonia lanceolata | Pursh | Montiaceae | 8 |
| Claytonia megarhiza | (A.Gray) Parry ex S.Watson | 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 |
| Clematis occidentalis | (Hornem.) DC. | Ranunculaceae | 8 |
| Clematis pitcheri | Torr. & A.Gray | Ranunculaceae | 8 |
| Cleome dodecandra | L. | Cleomaceae | 8 |
| Cleome jamesii | (Torr. & A.Gray) Govaerts | Cleomaceae | 8 |
| Cleome uniglandulosa | Cav. | Cleomaceae | 8 |
| Cleomella longipes | Torr. | Cleomaceae | 8 |
| Cleomella lutea | (Hook.) Roalson & J.C.Hall | Cleomaceae | 8 |
| Cleomella multicaulis | (DC.) J.C.Hall & Roalson | Cleomaceae | 8 |
| Cleomella refracta | (Engelm.) J.C.Hall & Roalson | Cleomaceae | 8 |
| Cleomella serrulata | (Pursh) Roalson & J.C.Hall | Cleomaceae | 8 |
| Clinopodium arkansanum | (Nutt.) House | Lamiaceae | 8 |
| Cochemiea grahamii | (Engelm.) Doweld | Cactaceae | 8 |
| Collinsia parviflora | Douglas ex Lindl. | Plantaginaceae | 8 |
| Collomia linearis | Nutt. | Polemoniaceae | 8 |
| Cologania angustifolia | Kunth | Fabaceae | 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 warnockii | M.C.Johnst. | Rhamnaceae | 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 |
| Conyza ramosissima | Cronquist | Asteraceae | 8 |
| Corallorhiza maculata | Raf. | Orchidaceae | 8 |
| Corallorhiza odontorhiza | (Willd.) Nutt. | Orchidaceae | 8 |
| Corallorhiza striata | Lindl. | Orchidaceae | 8 |
| Corallorhiza trifida | Châtel. | Orchidaceae | 8 |
| Corallorhiza wisteriana | Conrad | Orchidaceae | 8 |
| Cordylanthus wrightii | A.Gray | Orobanchaceae | 8 |
| Coreopsis grandiflora | Hogg ex Sweet | Asteraceae | 8 |
| Coreopsis lanceolata | L. | Asteraceae | 8 |
| Coreopsis tinctoria | Nutt. | Asteraceae | 8 |
| Cornus canadensis | L. | Cornaceae | 8 |
| Cornus sericea | L. | Cornaceae | 8 |
| Corydalis aurea | Willd. | Papaveraceae | 8 |
| Corydalis caseana | A.Gray | 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 |
| Crataegus chrysocarpa | Ashe | Rosaceae | 8 |
| Crataegus erythropoda | Ashe | Rosaceae | 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 |
| Crotalaria pumila | Ortega | Fabaceae | 8 |
| Croton dioicus | Cav. | Euphorbiaceae | 8 |
| Croton fruticulosus | Torr. | Euphorbiaceae | 8 |
| Croton glandulosus | L. | Euphorbiaceae | 8 |
| Croton lindheimerianus | Scheele | Euphorbiaceae | 8 |
| Croton monanthogynus | Michx. | Euphorbiaceae | 8 |
| Croton pottsii | (Klotzsch) Müll.Arg. | Euphorbiaceae | 8 |
| Croton texensis | (Klotzsch) Müll.Arg. | 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 fendleri | (A.Gray) Greene | Boraginaceae | 8 |
| Cryptantha gracilis | Osterh. | 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 |
| Cryptogramma acrostichoides | R.Br. | Pteridaceae | 8 |
| Cucurbita digitata | A.Gray | Cucurbitaceae | 8 |
| Cucurbita foetidissima | Kunth | Cucurbitaceae | 8 |
| Cuphea wrightii | A.Gray | Lythraceae | 8 |
| Cuscuta campestris | Yunck. | Convolvulaceae | 8 |
| Cuscuta cephalanthi | Engelm. | Convolvulaceae | 8 |
| Cuscuta coryli | Engelm. | Convolvulaceae | 8 |
| Cuscuta cuspidata | Engelm. | Convolvulaceae | 8 |
| Cuscuta gronovii | Willd. | Convolvulaceae | 8 |
| Cuscuta indecora | Choisy | Convolvulaceae | 8 |
| Cuscuta tuberculata | Brandegee | Convolvulaceae | 8 |
| Cuscuta umbellata | Kunth | Convolvulaceae | 8 |
| Cyclanthera naudiniana | Cogn. | Cucurbitaceae | 8 |
| Cylindropuntia bigelovii | (Engelm.) F.M.Knuth | Cactaceae | 8 |
| Cylindropuntia davisii | (Engelm. & J.M.Bigelow) 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 whipplei | (Engelm. & J.M.Bigelow) F.M.Knuth | Cactaceae | 8 |
| Cymopterus alpinus | A.Gray | Apiaceae | 8 |
| Cymopterus bakeri | M.E.Jones | Apiaceae | 8 |
| Cymopterus filifolius | (Mathias, Constance & W.L.Theob.) B.L.Turner | Apiaceae | 8 |
| Cymopterus glomeratus | (Nutt.) DC. | Apiaceae | 8 |
| Cymopterus hallii | (A.Gray) B.L.Turner | Apiaceae | 8 |
| Cymopterus hendersonii | (J.M.Coult. & Rose) Cronquist | 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 compressus | L. | Cyperaceae | 8 |
| Cyperus echinatus | (L.) Alph.Wood | Cyperaceae | 8 |
| Cyperus esculentus | L. | Cyperaceae | 8 |
| Cyperus fendlerianus | Boeckeler | Cyperaceae | 8 |
| Cyperus melanostachyus | Kunth | Cyperaceae | 8 |
| Cyperus odoratus | L. | Cyperaceae | 8 |
| Cyperus pseudothyrsiflorus | (Kük.) R.Carter & S.D.Jones | Cyperaceae | 8 |
| Cyperus retroflexus | Buckley | Cyperaceae | 8 |
| Cyperus schweinitzii | Torr. | Cyperaceae | 8 |
| Cyperus sesquiflorus | (Torr.) Mattf. & Kük. | Cyperaceae | 8 |
| Cyperus sphaerolepis | Boeckeler | Cyperaceae | 8 |
| Cyperus squarrosus | L. | Cyperaceae | 8 |
| Cyperus strigosus | L. | Cyperaceae | 8 |
| Cyperus subsquarrosus | (Muhl.) Bauters | Cyperaceae | 8 |
| Cyperus tetragonus | Elliott | Cyperaceae | 8 |
| Cyphomeris gypsophiloides | (M.Martens & Galeotti) Standl. | Nyctaginaceae | 8 |
| Cypripedium parviflorum | Salisb. | Orchidaceae | 8 |
| Cyrtorhyncha ranunculina | Nutt. | Ranunculaceae | 8 |
| Cystopteris bulbifera | (L.) Bernh. | Cystopteridaceae | 8 |
| Cystopteris fragilis | (L.) Bernh. | Cystopteridaceae | 8 |
| Cystopteris reevesiana | Lellinger | Cystopteridaceae | 8 |
| Cystopteris tenuis | (Michx.) Desv. | Cystopteridaceae | 8 |
| Dactylorhiza viridis | (L.) R.M.Bateman, Pridgeon & M.W.Chase | Orchidaceae | 8 |
| Dalea albiflora | A.Gray | Fabaceae | 8 |
| Dalea aurea | Nutt. ex Pursh | Fabaceae | 8 |
| Dalea bicolor | Humb. & Bonpl. ex Willd. | Fabaceae | 8 |
| Dalea candida | Willd. | Fabaceae | 8 |
| Dalea cylindriceps | Barneby | Fabaceae | 8 |
| Dalea enneandra | Nutt. | Fabaceae | 8 |
| Dalea formosa | Torr. | Fabaceae | 8 |
| Dalea frutescens | A.Gray | Fabaceae | 8 |
| Dalea greggii | A.Gray | Fabaceae | 8 |
| Dalea jamesii | (Torr.) Torr. & A.Gray | Fabaceae | 8 |
| Dalea lanata | Spreng. | Fabaceae | 8 |
| Dalea leporina | (Aiton) Bullock | Fabaceae | 8 |
| Dalea nana | Torr. ex A.Gray | Fabaceae | 8 |
| Dalea neomexicana | (A.Gray) Cory | Fabaceae | 8 |
| Dalea pogonathera | A.Gray | Fabaceae | 8 |
| Dalea polygonoides | A.Gray | Fabaceae | 8 |
| Dalea pulchra | Gentry | Fabaceae | 8 |
| Dalea purpurea | Vent. | Fabaceae | 8 |
| Dalea rubescens | S.Watson | Fabaceae | 8 |
| Dalea scariosa | S.Watson | Fabaceae | 8 |
| Dalea tenuifolia | (A.Gray) Shinners | Fabaceae | 8 |
| Dalea urceolata | Greene | Fabaceae | 8 |
| Dalea versicolor | Zucc. | Fabaceae | 8 |
| Dalea villosa | (Nutt.) Spreng. | Fabaceae | 8 |
| Dalea wrightii | A.Gray | Fabaceae | 8 |
| Danthonia intermedia | Vasey | Poaceae | 8 |
| Danthonia spicata | (L.) Roem. & Schult. | Poaceae | 8 |
| Dasiphora fruticosa | (L.) Rydb. | Rosaceae | 8 |
| Dasylirion leiophyllum | Engelm. ex Trel. | Asparagaceae | 8 |
| Dasylirion wheeleri | S.Watson ex Rothr. | Asparagaceae | 8 |
| Datura wrightii | Regel | Solanaceae | 8 |
| Daucus pusillus | Michx. | Apiaceae | 8 |
| Delphinium barbeyi | (Huth) Huth | Ranunculaceae | 8 |
| Delphinium geraniifolium | Rydb. | Ranunculaceae | 8 |
| Delphinium nuttallianum | Pritz. | Ranunculaceae | 8 |
| Delphinium occidentale | S.Watson ex J.M.Coult. | Ranunculaceae | 8 |
| Delphinium scaposum | Greene | Ranunculaceae | 8 |
| Delphinium scopulorum | A.Gray | Ranunculaceae | 8 |
| Delphinium wootonii | Rydb. | Ranunculaceae | 8 |
| Dermatophyllum secundiflorum | (Ortega) Gandhi & Reveal | Fabaceae | 8 |
| Deschampsia danthonioides | (Trin.) Benth. | Poaceae | 8 |
| Deschampsia elongata | (Hook.) Munro | Poaceae | 8 |
| Descurainia californica | (A.Gray) O.E.Schulz | Brassicaceae | 8 |
| Descurainia incana | (Bernh. ex Fisch. & C.A.Mey.) Dorn | Brassicaceae | 8 |
| Descurainia incisa | (Engelm.) Britton | Brassicaceae | 8 |
| Descurainia longepedicellata | (E.Fourn.) O.E.Schulz | Brassicaceae | 8 |
| Descurainia pinnata | (Walter) Britton | Brassicaceae | 8 |
| Desmanthus cooleyi | (Eaton) Trel. ex Branner & Coville | Fabaceae | 8 |
| Desmanthus illinoensis | (Michx.) MacMill. ex B.L.Rob. & Fernald | Fabaceae | 8 |
| Desmanthus velutinus | Scheele | Fabaceae | 8 |
| Desmodium batocaulon | A.Gray | Fabaceae | 8 |
| Desmodium grahamii | A.Gray | Fabaceae | 8 |
| Desmodium procumbens | (Mill.) C.L.Hitchc. | Fabaceae | 8 |
| Desmodium psilophyllum | Schltdl. | Fabaceae | 8 |
| Desmodium rosei | B.G.Schub. | Fabaceae | 8 |
| Diaperia prolifera | (Nutt. ex DC.) Nutt. | Asteraceae | 8 |
| Diaperia verna | (Raf.) Morefield | Asteraceae | 8 |
| Dichanthelium acuminatum | (Sw.) Gould & C.A.Clark | Poaceae | 8 |
| Dichanthelium lanuginosum | (Elliott) Gould | Poaceae | 8 |
| Dichanthelium lindheimeri | (Nash) Gould | Poaceae | 8 |
| Dichanthelium linearifolium | (Scribn.) Gould | Poaceae | 8 |
| Dichanthelium oligosanthes | (Schult.) Gould | Poaceae | 8 |
| Dichelostemma capitatum | (Benth.) Alph.Wood | Asparagaceae | 8 |
| Dichondra argentea | Humb. & Bonpl. ex Willd. | Convolvulaceae | 8 |
| Dichondra brachypoda | Wooton & Standl. | Convolvulaceae | 8 |
| Dicliptera resupinata | (Vahl) Juss. | Acanthaceae | 8 |
| Dicoria canescens | A.Gray | Asteraceae | 8 |
| Dicranocarpus parviflorus | 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 |
| Dimorphocarpa candicans | (Raf.) Rollins | Brassicaceae | 8 |
| Diplachne fusca | (L.) P.Beauv. | Poaceae | 8 |
| Disakisperma dubium | (Kunth) P.M.Peterson & N.Snow | Poaceae | 8 |
| Distichlis spicata | (L.) Greene | Poaceae | 8 |
| Ditaxis humilis | (Engelm. & A.Gray) Pax | Euphorbiaceae | 8 |
| Ditaxis mercurialina | (Nutt.) J.M.Coult. | Euphorbiaceae | 8 |
| Ditaxis serrata | (Torr.) A.Heller | Euphorbiaceae | 8 |
| Draba albertina | Greene | Brassicaceae | 8 |
| Draba aurea | Vahl ex Hornem. | Brassicaceae | 8 |
| Draba cana | Rydb. | Brassicaceae | 8 |
| Draba crassa | Rydb. | Brassicaceae | 8 |
| Draba heilii | Al-Shehbaz | Brassicaceae | 8 |
| Draba helleriana | Greene | Brassicaceae | 8 |
| Draba mogollonica | Greene | Brassicaceae | 8 |
| Draba nemorosa | L. | 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 arguta | (Pursh) Rydb. | Rosaceae | 8 |
| Drymocallis convallaria | (Rydb.) Rydb. | Rosaceae | 8 |
| Drymocallis fissa | (Nutt.) Rydb. | Rosaceae | 8 |
| Drymocallis glandulosa | (Lindl.) Rydb. | Rosaceae | 8 |
| Dryopetalon runcinatum | A.Gray | Brassicaceae | 8 |
| Dryopteris filix-mas | (L.) Schott | Dryopteridaceae | 8 |
| Dyschoriste decumbens | (A.Gray) Kuntze | Acanthaceae | 8 |
| Dyssodia papposa | (Vent.) Hitchc. | Asteraceae | 8 |
| Echeandia flavescens | (Schult. & Schult.f.) Cruden | Asparagaceae | 8 |
| Echinacea angustifolia | DC. | Asteraceae | 8 |
| Echinocereus coccineus | Engelm. | Cactaceae | 8 |
| Echinocereus engelmannii | (Parry ex Engelm.) Lem. | Cactaceae | 8 |
| Echinocereus fendleri | (Engelm.) Sencke ex J.N.Haage | Cactaceae | 8 |
| Echinocereus santaritensis | W.Blum & Rutow | Cactaceae | 8 |
| Echinochloa muricata | (P.Beauv.) Fernald | Poaceae | 8 |
| Echinocystis lobata | (Michx.) Torr. & A.Gray | Cucurbitaceae | 8 |
| Echinodorus berteroi | (Spreng.) Fassett | Alismataceae | 8 |
| Echinopepon wrightii | (A.Gray) S.Watson | Cucurbitaceae | 8 |
| Eclipta prostrata | (L.) L. | Asteraceae | 8 |
| Elatine brachysperma | A.Gray | Elatinaceae | 8 |
| Eleocharis acicularis | (L.) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis atropurpurea | (Retz.) J.Presl & C.Presl | Cyperaceae | 8 |
| Eleocharis compressa | Sull. | 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 obtusa | (Willd.) Schult. | Cyperaceae | 8 |
| Eleocharis palustris | (L.) Roem. & Schult. | Cyperaceae | 8 |
| Eleocharis quinqueflora | (Hartmann) O.Schwarz | Cyperaceae | 8 |
| Eleocharis rostellata | (Torr.) Torr. | Cyperaceae | 8 |
| Eleocharis uniglumis | (Link) Schult. | Cyperaceae | 8 |
| Ellisia nyctelea | (L.) L. | Hydrophyllaceae | 8 |
| Elodea canadensis | Michx. | Hydrocharitaceae | 8 |
| Elodea nuttallii | (Planch.) H.St.John | Hydrocharitaceae | 8 |
| Elymus canadensis | L. | Poaceae | 8 |
| Elymus curvatus | Piper | 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 villosus | Muhl. ex Willd. | Poaceae | 8 |
| Elymus violaceus | (Hornem.) J.Feilberg | Poaceae | 8 |
| Elymus virginicus | L. | Poaceae | 8 |
| Elytraria imbricata | (Vahl) Pers. | Acanthaceae | 8 |
| Encelia virginensis | A.Nelson | Asteraceae | 8 |
| Engelmannia peristenia | (Raf.) Goodman & C.A.Lawson | Asteraceae | 8 |
| Enneapogon desvauxii | P.Beauv. | Poaceae | 8 |
| Ephedra antisyphilitica | Berland. ex C.A.Mey. | Ephedraceae | 8 |
| Ephedra aspera | Engelm. ex S.Watson | Ephedraceae | 8 |
| Ephedra cutleri | Peebles | Ephedraceae | 8 |
| Ephedra torreyana | S.Watson | Ephedraceae | 8 |
| Ephedra trifurca | Torr. ex S.Watson | Ephedraceae | 8 |
| Ephedra viridis | Coville | Ephedraceae | 8 |
| Epilobium anagallidifolium | Lam. | Onagraceae | 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 hornemannii | Rchb. | Onagraceae | 8 |
| Epilobium lactiflorum | Hausskn. | Onagraceae | 8 |
| Epilobium leptophyllum | Raf. | Onagraceae | 8 |
| Epilobium palustre | L. | 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 curtipedicellata | Buckley | Poaceae | 8 |
| Eragrostis hypnoides | (Lam.) Britton, Sterns & Poggenb. | Poaceae | 8 |
| Eragrostis intermedia | Hitchc. | Poaceae | 8 |
| Eragrostis pectinacea | (Michx.) Nees | Poaceae | 8 |
| Eragrostis reptans | (Michx.) Nees | Poaceae | 8 |
| Eragrostis secundiflora | J.Presl | Poaceae | 8 |
| Eragrostis sessilispica | Buckley | Poaceae | 8 |
| Eragrostis spectabilis | (Pursh) Steud. | Poaceae | 8 |
| Eragrostis trichodes | (Nutt.) Alph.Wood | Poaceae | 8 |
| Eremocarya micrantha | (Torr.) Greene | Boraginaceae | 8 |
| Eremogone aculeata | (S.Watson) Ikonn. | Caryophyllaceae | 8 |
| Eremogone eastwoodiae | (Rydb.) Ikonn. | Caryophyllaceae | 8 |
| Eremogone fendleri | (A.Gray) Ikonn. | Caryophyllaceae | 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 |
| 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 |
| Erigeron aphanactis | Greene | Asteraceae | 8 |
| Erigeron arizonicus | A.Gray | Asteraceae | 8 |
| Erigeron bellidiastrum | Nutt. | Asteraceae | 8 |
| Erigeron canadensis | L. | Asteraceae | 8 |
| Erigeron concinnus | Torr. & A.Gray | Asteraceae | 8 |
| Erigeron divergens | Torr. & A.Gray | Asteraceae | 8 |
| Erigeron elatior | Greene | Asteraceae | 8 |
| Erigeron flagellaris | A.Gray | Asteraceae | 8 |
| Erigeron formosissimus | Greene | Asteraceae | 8 |
| Erigeron glabellus | Nutt. | Asteraceae | 8 |
| Erigeron glacialis | (Nutt.) A.Nelson | Asteraceae | 8 |
| Erigeron lonchophyllus | Hook. | Asteraceae | 8 |
| Erigeron modestus | A.Gray | Asteraceae | 8 |
| Erigeron neomexicanus | A.Gray | Asteraceae | 8 |
| Erigeron nivalis | Nutt. | Asteraceae | 8 |
| Erigeron oreophilus | Greenm. | Asteraceae | 8 |
| Erigeron philadelphicus | L. | Asteraceae | 8 |
| Erigeron pinnatisectus | (A.Gray) A.Nelson | Asteraceae | 8 |
| Erigeron speciosus | (Lindl.) DC. | Asteraceae | 8 |
| Erigeron strigosus | Muhl. ex Willd. | Asteraceae | 8 |
| Erigeron tracyi | Greene | Asteraceae | 8 |
| Erigeron ursinus | D.C.Eaton | Asteraceae | 8 |
| Erigeron utahensis | A.Gray | Asteraceae | 8 |
| Erigeron vetensis | Rydb. | 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 pinetorum | (M.E.Jones) Romasch. | Poaceae | 8 |
| Eriogonum abertianum | Torr. | Polygonaceae | 8 |
| Eriogonum alatum | Torr. | Polygonaceae | 8 |
| Eriogonum annuum | Nutt. | Polygonaceae | 8 |
| Eriogonum arcuatum | Greene | Polygonaceae | 8 |
| Eriogonum cernuum | Nutt. | Polygonaceae | 8 |
| Eriogonum corymbosum | Benth. | Polygonaceae | 8 |
| Eriogonum deflexum | Torr. | Polygonaceae | 8 |
| Eriogonum effusum | Nutt. | Polygonaceae | 8 |
| Eriogonum havardii | S.Watson | 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 lonchophyllum | Torr. & A.Gray | Polygonaceae | 8 |
| Eriogonum longifolium | Nutt. | Polygonaceae | 8 |
| Eriogonum maculatum | A.Heller | Polygonaceae | 8 |
| Eriogonum ovalifolium | Nutt. | Polygonaceae | 8 |
| Eriogonum palmerianum | Reveal | Polygonaceae | 8 |
| Eriogonum polycladon | Benth. | Polygonaceae | 8 |
| Eriogonum racemosum | Nutt. | Polygonaceae | 8 |
| Eriogonum rotundifolium | Benth. | Polygonaceae | 8 |
| Eriogonum shockleyi | S.Watson | Polygonaceae | 8 |
| Eriogonum tenellum | Torr. | Polygonaceae | 8 |
| Eriogonum thurberi | Torr. | Polygonaceae | 8 |
| Eriogonum trichopes | Torr. | Polygonaceae | 8 |
| Eriogonum umbellatum | Torr. | Polygonaceae | 8 |
| Eriogonum wootonii | (Reveal) Reveal | Polygonaceae | 8 |
| Eriogonum wrightii | Torr. ex Benth. | Polygonaceae | 8 |
| Erioneuron avenaceum | (Kunth) Tateoka | Poaceae | 8 |
| Erioneuron pilosum | (Buckley) Nash | Poaceae | 8 |
| Eriophorum angustifolium | Honck. | Cyperaceae | 8 |
| Eriophorum gracile | Roth | Cyperaceae | 8 |
| Eriophorum scheuchzeri | Hoppe | Cyperaceae | 8 |
| Eriophyllum lanosum | (A.Gray) A.Gray | Asteraceae | 8 |
| Erodium texanum | A.Gray | Geraniaceae | 8 |
| Eryngium heterophyllum | Engelm. | Apiaceae | 8 |
| Eryngium lemmonii | J.M.Coult. & Rose | Apiaceae | 8 |
| Erysimum asperum | (Nutt.) DC. | Brassicaceae | 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 |
| Erythrina flabelliformis | Kearney | Fabaceae | 8 |
| Erythronium grandiflorum | Pursh | Liliaceae | 8 |
| Eschscholzia californica | Cham. | Papaveraceae | 8 |
| Eucrypta micrantha | (Torr.) A.Heller | Hydrophyllaceae | 8 |
| Euphorbia abramsiana | L.C.Wheeler | Euphorbiaceae | 8 |
| Euphorbia acuta | Engelm. | Euphorbiaceae | 8 |
| Euphorbia albomarginata | Torr. & A.Gray | Euphorbiaceae | 8 |
| Euphorbia antisyphilitica | Zucc. | Euphorbiaceae | 8 |
| Euphorbia arizonica | Engelm. | Euphorbiaceae | 8 |
| Euphorbia bifurcata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia brachycera | Engelm. | Euphorbiaceae | 8 |
| Euphorbia capitellata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia carunculata | Waterf. | Euphorbiaceae | 8 |
| Euphorbia chaetocalyx | (Boiss.) Tidestr. | Euphorbiaceae | 8 |
| Euphorbia chamaesula | Boiss. | Euphorbiaceae | 8 |
| Euphorbia crenulata | Engelm. | 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 geyeri | Engelm. | Euphorbiaceae | 8 |
| Euphorbia glyptosperma | Engelm. | Euphorbiaceae | 8 |
| Euphorbia heterophylla | L. | Euphorbiaceae | 8 |
| Euphorbia hexagona | Nutt. ex Spreng. | Euphorbiaceae | 8 |
| Euphorbia hirta | L. | Euphorbiaceae | 8 |
| Euphorbia hyssopifolia | L. | Euphorbiaceae | 8 |
| Euphorbia indivisa | (Engelm.) Tidestr. | Euphorbiaceae | 8 |
| Euphorbia lata | Engelm. | Euphorbiaceae | 8 |
| Euphorbia lurida | Engelm. | Euphorbiaceae | 8 |
| Euphorbia maculata | L. | Euphorbiaceae | 8 |
| Euphorbia marginata | Pursh | Euphorbiaceae | 8 |
| Euphorbia micromera | Boiss. | Euphorbiaceae | 8 |
| Euphorbia missurica | Raf. | Euphorbiaceae | 8 |
| Euphorbia nutans | Lag. | Euphorbiaceae | 8 |
| Euphorbia parryi | Engelm. | Euphorbiaceae | 8 |
| Euphorbia prostrata | Aiton | Euphorbiaceae | 8 |
| Euphorbia rayturneri | V.W.Steinm. & Jercinovic | Euphorbiaceae | 8 |
| Euphorbia revoluta | Engelm. | Euphorbiaceae | 8 |
| Euphorbia serpens | Kunth | Euphorbiaceae | 8 |
| Euphorbia serpillifolia | Pers. | Euphorbiaceae | 8 |
| Euphorbia serrula | Engelm. | Euphorbiaceae | 8 |
| Euphorbia setiloba | Engelm. | Euphorbiaceae | 8 |
| Euphorbia spathulata | Lam. | Euphorbiaceae | 8 |
| Euphorbia stictospora | Engelm. | Euphorbiaceae | 8 |
| Euphorbia vermiculata | Raf. | Euphorbiaceae | 8 |
| Euphorbia villifera | Scheele | Euphorbiaceae | 8 |
| Euphrosyne dealbata | (A.Gray) Panero | Asteraceae | 8 |
| Euploca convolvulacea | Nutt. | Heliotropiaceae | 8 |
| Euploca greggii | (Torr.) Halse & Feuillet | Heliotropiaceae | 8 |
| Eurytaenia hinckleyi | Mathias & Constance | Apiaceae | 8 |
| Eustoma exaltatum | (L.) Salisb. ex G.Don | Gentianaceae | 8 |
| Eustoma russellianum | (Hook.) G.Don | Gentianaceae | 8 |
| Euthamia graminifolia | (L.) Nutt. | Asteraceae | 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 hamatacanthus | (Muehlenpf.) Britton & Rose | Cactaceae | 8 |
| Ferocactus uncinatus | (Galeotti ex Pfeiff.) Britton & Rose | 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 kingii | (S.Watson) Cassidy | Poaceae | 8 |
| Festuca microstachys | Nutt. | Poaceae | 8 |
| Festuca octoflora | Walter | Poaceae | 8 |
| Festuca rubra | L. | Poaceae | 8 |
| Fimbristylis puberula | (Michx.) Vahl | 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 |
| Frankenia jamesii | Torr. ex A.Gray | Frankeniaceae | 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 papillosa | Lingelsh. | Oleaceae | 8 |
| Fraxinus velutina | Torr. | Oleaceae | 8 |
| Fritillaria atropurpurea | Nutt. | Liliaceae | 8 |
| Froelichia arizonica | Thornber ex Standl. | Amaranthaceae | 8 |
| Froelichia floridana | (Nutt.) Moq. | Amaranthaceae | 8 |
| Froelichia gracilis | (Hook.) Moq. | Amaranthaceae | 8 |
| Fuirena simplex | Vahl | Cyperaceae | 8 |
| Funastrum crispum | (Benth.) Schltr. | Apocynaceae | 8 |
| Funastrum cynanchoides | (Decne.) Schltr. | Apocynaceae | 8 |
| Funastrum heterophyllum | (Engelm. ex Torr.) Standl. | Apocynaceae | 8 |
| Gagea serotina | (L.) Ker Gawl. | Liliaceae | 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 pilosum | Aiton | Rubiaceae | 8 |
| Galium proliferum | A.Gray | Rubiaceae | 8 |
| Galium trifidum | L. | Rubiaceae | 8 |
| Galium triflorum | Michx. | Rubiaceae | 8 |
| Galium wrightii | A.Gray | Rubiaceae | 8 |
| Gamochaeta stagnalis | (I.M.Johnst.) Anderb. | Asteraceae | 8 |
| Garrya flavescens | S.Watson | Garryaceae | 8 |
| Garrya goldmanii | Wooton & Standl. | Garryaceae | 8 |
| Garrya wrightii | Torr. | Garryaceae | 8 |
| Gaultheria humifusa | (Graham) Rydb. | Ericaceae | 8 |
| Gayophytum ramosissimum | Torr. & A.Gray | Onagraceae | 8 |
| Gentiana affinis | Griseb. | Gentianaceae | 8 |
| Gentiana algida | Pall. | Gentianaceae | 8 |
| Gentiana parryi | Engelm. | Gentianaceae | 8 |
| Gentianopsis barbellata | (Engelm.) Iltis | Gentianaceae | 8 |
| Gentianopsis thermalis | (Kuntze) Iltis | Gentianaceae | 8 |
| Geranium caespitosum | E.James | Geraniaceae | 8 |
| Geranium carolinianum | L. | Geraniaceae | 8 |
| Geranium dodecatheoides | P.J.Alexander & Aedo | 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 rivale | L. | Rosaceae | 8 |
| Geum rossii | (R.Br.) Ser. | Rosaceae | 8 |
| Geum triflorum | Pursh | Rosaceae | 8 |
| Gilia clokeyi | H.Mason | Polemoniaceae | 8 |
| Gilia inconspicua | (Sm.) Sweet | Polemoniaceae | 8 |
| Gilia lyndana | Allred | Polemoniaceae | 8 |
| Gilia mexicana | A.D.Grant & V.E.Grant | Polemoniaceae | 8 |
| Gilia ophthalmoides | Brand | Polemoniaceae | 8 |
| Gilia sinuata | Douglas ex Benth. | Polemoniaceae | 8 |
| Gilia stellata | A.Heller | Polemoniaceae | 8 |
| Giliastrum acerosum | (A.Gray) Rydb. | Polemoniaceae | 8 |
| Giliastrum incisum | (Benth.) J.M.Porter | Polemoniaceae | 8 |
| Giliastrum rigidulum | 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 lanuparonychioides | T. Ortuño & Borsch | 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 |
| Graphephorum canescens | (Buckley) Röser & Tkach | Poaceae | 8 |
| Graphephorum wolfii | (Vasey) Coult. | Poaceae | 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 scabra | Greene | Asteraceae | 8 |
| Grindelia squarrosa | (Pursh) Dunal | Asteraceae | 8 |
| Grusonia clavata | (Engelm.) H.Rob. | Cactaceae | 8 |
| Grusonia emoryi | (Engelm.) Pinkava | Cactaceae | 8 |
| Grusonia grahamii | (Engelm.) H.Rob. | Cactaceae | 8 |
| Guilleminea densa | (Humb. & Bonpl. ex Schult.) Moq. | Amaranthaceae | 8 |
| Gutierrezia dracunculoides | (DC.) O.Hoffm. | Asteraceae | 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 |
| Hamogalium bifolium | (S.Watson) Kadereit & Schneew. | Rubiaceae | 8 |
| Haplophyton crooksii | (L.D.Benson) L.D.Benson | Apocynaceae | 8 |
| Harbouria trachypleura | J.M.Coult. & Rose | Apiaceae | 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 costata | A.Gray | Lamiaceae | 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 |
| Hedeoma pulcherrima | Wooton & Standl. | Lamiaceae | 8 |
| Hedosyne ambrosiifolia | (A.Gray) Strother | Asteraceae | 8 |
| Hedysarum boreale | Nutt. | Fabaceae | 8 |
| Helenium autumnale | L. | Asteraceae | 8 |
| Helenium microcephalum | DC. | Asteraceae | 8 |
| Helianthella microcephala | A.Gray | Asteraceae | 8 |
| Helianthella quinquenervis | (Hook.) A.Gray | Asteraceae | 8 |
| Helianthus ciliaris | DC. | Asteraceae | 8 |
| Helianthus laciniatus | A.Gray | Asteraceae | 8 |
| Helianthus nuttallii | Torr. & A.Gray | Asteraceae | 8 |
| Helianthus pauciflorus | Nutt. | Asteraceae | 8 |
| Helianthus petiolaris | Nutt. | Asteraceae | 8 |
| Helictochloa hookeri | (Scribn.) Romero Zarco | Poaceae | 8 |
| Heliomeris longifolia | Cockerell | Asteraceae | 8 |
| Heliomeris multiflora | Nutt. | Asteraceae | 8 |
| Heliopsis helianthoides | Sweet | Asteraceae | 8 |
| Heliopsis parvifolia | A.Gray | Asteraceae | 8 |
| Heliotropium curassavicum | L. | Heliotropiaceae | 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 |
| Hesperocyparis arizonica | (Greene) Bartel | Cupressaceae | 8 |
| Hesperostipa comata | (Trin. & Rupr.) Barkworth | Poaceae | 8 |
| Hesperostipa neomexicana | (Thurb.) Barkworth | Poaceae | 8 |
| Hesperostipa spartea | (Trin.) Barkworth | Poaceae | 8 |
| Heteranthera limosa | (Sw.) Willd. | Pontederiaceae | 8 |
| Heteropogon contortus | (L.) P.Beauv. ex Roem. & Schult. | Poaceae | 8 |
| Heterosperma pinnatum | Cav. | Asteraceae | 8 |
| Heterotheca canescens | (DC.) Shinners | Asteraceae | 8 |
| Heterotheca fulcrata | (Greene) Shinners | Asteraceae | 8 |
| Heterotheca pumila | (Greene) Semple | 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 hallii | A.Gray | 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 |
| Heuchera soltisii | R.A.Folk & P.J.Alexander | Saxifragaceae | 8 |
| Heuchera woodsiaphila | P.J.Alexander | 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 |
| Hieracium triste | Willd. ex Spreng. | 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 oxycarpa | Benth. | Fabaceae | 8 |
| Holodiscus discolor | (Pursh) Maxim. | Rosaceae | 8 |
| Homalocephala texensis | (Hopffer) Britton & Rose | Cactaceae | 8 |
| Hopia obtusa | (Kunth) Zuloaga & Morrone | Poaceae | 8 |
| Hordeum brachyantherum | Nevski | Poaceae | 8 |
| Hordeum jubatum | L. | Poaceae | 8 |
| Houstonia acerosa | (A.Gray) Benth. & Hook.f. | Rubiaceae | 8 |
| Houstonia humifusa | (Engelm. ex A.Gray) A.Gray | Rubiaceae | 8 |
| Houstonia rubra | Cav. | Rubiaceae | 8 |
| Houstonia wrightii | A.Gray | Rubiaceae | 8 |
| Humulus neomexicanus | (A.Nelson & Cockerell) Rydb. | Cannabaceae | 8 |
| Huperzia lucidula | (Michx.) Trevis. | Lycopodiaceae | 8 |
| Hydrocotyle verticillata | Thunb. | Araliaceae | 8 |
| Hydrophyllum fendleri | (A.Gray) A.Heller | Hydrophyllaceae | 8 |
| Hymenopappus biennis | B.L.Turner | Asteraceae | 8 |
| Hymenopappus filifolius | Hook. | Asteraceae | 8 |
| Hymenopappus flavescens | A.Gray | Asteraceae | 8 |
| Hymenopappus mexicanus | A.Gray | Asteraceae | 8 |
| Hymenopappus tenuifolius | Pursh | Asteraceae | 8 |
| Hymenothrix dissecta | (A.Gray) B.G.Baldwin | Asteraceae | 8 |
| Hymenothrix pedata | (A.Gray) B.G.Baldwin | Asteraceae | 8 |
| Hymenothrix wislizeni | A.Gray | Asteraceae | 8 |
| Hymenothrix wrightii | A.Gray | Asteraceae | 8 |
| Hymenoxys bigelovii | (A.Gray) K.F.Parker | Asteraceae | 8 |
| Hymenoxys brandegeei | (Porter ex A.Gray) K.F.Parker | 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 mutilum | L. | Hypericaceae | 8 |
| Hypericum scouleri | Hook. | Hypericaceae | 8 |
| Hypopitys monotropa | Crantz | Ericaceae | 8 |
| Hypoxis hirsuta | (L.) Coville | Hypoxidaceae | 8 |
| Ibervillea lindheimeri | (A.Gray) Greene | Cucurbitaceae | 8 |
| Ibervillea tenuisecta | (A.Gray) Small | Cucurbitaceae | 8 |
| Iliamna rivularis | (Douglas) Greene | Malvaceae | 8 |
| Ipomoea barbatisepala | A.Gray | Convolvulaceae | 8 |
| Ipomoea capillacea | (Kunth) G.Don | Convolvulaceae | 8 |
| Ipomoea cardiophylla | A.Gray | Convolvulaceae | 8 |
| Ipomoea cordatotriloba | Dennst. | Convolvulaceae | 8 |
| Ipomoea costellata | Torr. | Convolvulaceae | 8 |
| Ipomoea cristulata | Hallier f. | Convolvulaceae | 8 |
| Ipomoea dumetorum | Willd. | Convolvulaceae | 8 |
| Ipomoea gilana | K.Keith & J.A.McDonald | Convolvulaceae | 8 |
| Ipomoea leptophylla | Torr. | Convolvulaceae | 8 |
| Ipomoea lindheimeri | A.Gray | Convolvulaceae | 8 |
| Ipomoea longifolia | Benth. | Convolvulaceae | 8 |
| Ipomoea plummerae | A.Gray | Convolvulaceae | 8 |
| Ipomoea pubescens | Lam. | Convolvulaceae | 8 |
| Ipomopsis aggregata | (Pursh) V.E.Grant | 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 multiflora | (Nutt.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis polycladon | (Torr.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis pumila | (Nutt.) V.E.Grant | Polemoniaceae | 8 |
| Ipomopsis spicata | (Nutt.) 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 pluriflora | (Torr. & A.Gray) Greene | Asteraceae | 8 |
| Isocoma tenuisecta | Greene | Asteraceae | 8 |
| Isoetes bolanderi | Engelm. | Isoetaceae | 8 |
| Iva annua | L. | Asteraceae | 8 |
| Iva axillaris | Pursh | Asteraceae | 8 |
| Jamesia americana | Torr. & A.Gray | Hydrangeaceae | 8 |
| Jatropha cathartica | Terán & Berland. | Euphorbiaceae | 8 |
| Jatropha macrorhiza | Benth. | Euphorbiaceae | 8 |
| Jefea brevifolia | (A.Gray) Strother | Asteraceae | 8 |
| Johnstonella albida | (Kunth) M.E.Mabry & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella angustifolia | (Torr.) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella mexicana | (Brandegee) M.E.Mabry & M.G.Simpson | Boraginaceae | 8 |
| Johnstonella pusilla | (Torr. & A.Gray) Hasenstab & M.G.Simpson | Boraginaceae | 8 |
| Juglans major | (Torr.) A.Heller | Juglandaceae | 8 |
| Juglans microcarpa | Berland. | Juglandaceae | 8 |
| Juncus acuminatus | Michx. | Juncaceae | 8 |
| Juncus alpinoarticulatus | Chaix | Juncaceae | 8 |
| Juncus articulatus | L. | Juncaceae | 8 |
| Juncus balticus | Willd. | Juncaceae | 8 |
| Juncus bufonius | L. | Juncaceae | 8 |
| Juncus castaneus | Sm. | Juncaceae | 8 |
| Juncus dichotomus | Elliott | Juncaceae | 8 |
| Juncus drummondii | E.Mey. | Juncaceae | 8 |
| Juncus dudleyi | Wiegand | Juncaceae | 8 |
| Juncus interior | Wiegand | Juncaceae | 8 |
| Juncus marginatus | Rostk. | Juncaceae | 8 |
| Juncus mertensianus | Bong. | Juncaceae | 8 |
| Juncus nodosus | L. | Juncaceae | 8 |
| Juncus parryi | Engelm. | Juncaceae | 8 |
| Juncus tenuis | Willd. | Juncaceae | 8 |
| Juncus torreyi | Coville | Juncaceae | 8 |
| Juncus xiphioides | E.Mey. | Juncaceae | 8 |
| Juniperus arizonica | (R.P.Adams) R.P.Adams | Cupressaceae | 8 |
| Juniperus 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 pilosella | (Nees) Hilsenb. | Acanthaceae | 8 |
| Kallstroemia californica | (S.Watson) Vail | Zygophyllaceae | 8 |
| Kallstroemia grandiflora | Torr. ex A.Gray | Zygophyllaceae | 8 |
| Kallstroemia parviflora | Norton | Zygophyllaceae | 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 biennis | (Moench) Fernald | 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 |
| Lantana achyranthifolia | Desf. | Verbenaceae | 8 |
| Lantana urticoides | Hayek | Verbenaceae | 8 |
| Lappula occidentalis | (S.Watson) Greene | Boraginaceae | 8 |
| Larrea tridentata | (DC.) Coville | Zygophyllaceae | 8 |
| Lasianthaea podocephala | (A.Gray) K.M.Becker | Asteraceae | 8 |
| Lathyrus brachycalyx | Rydb. | Fabaceae | 8 |
| Lathyrus decaphyllus | Pursh | Fabaceae | 8 |
| Lathyrus eucosmus | Butters & H.St.John | Fabaceae | 8 |
| Lathyrus graminifolius | (S.Watson) T.G.White | Fabaceae | 8 |
| Lathyrus lanszwertii | Kellogg | Fabaceae | 8 |
| Lathyrus venosus | Muhl. ex Willd. | Fabaceae | 8 |
| Layia glandulosa | (Hook.) Hook. & Arn. | Asteraceae | 8 |
| Lechea mucronata | Raf. | Cistaceae | 8 |
| Lechea tenuifolia | Michx. | Cistaceae | 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 austrinum | Small | Brassicaceae | 8 |
| Lepidium densiflorum | Schrad. | 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 |
| Lepidospartum burgessii | B.L.Turner | Asteraceae | 8 |
| Leptochloa crinita | (Lag.) P.M.Peterson & N.Snow | Poaceae | 8 |
| Leptochloa panicea | (Retz.) Ohwi | Poaceae | 8 |
| Leucaena retusa | Benth. | Fabaceae | 8 |
| Leucocrinum montanum | Nutt. ex A.Gray | Asparagaceae | 8 |
| Leucophyllum minus | A.Gray | Scrophulariaceae | 8 |
| Lewisia nevadensis | (A.Gray) B.L.Rob. | Montiaceae | 8 |
| Lewisia pygmaea | (A.Gray) B.L.Rob. | Montiaceae | 8 |
| Leymus cinereus | (Scribn. & Merr.) Á.Löve | Poaceae | 8 |
| Leymus triticoides | (Buckley) Pilg. | Poaceae | 8 |
| Liatris ligulistylis | (A.Nelson) K.Schum. | Asteraceae | 8 |
| Liatris punctata | Hook. | Asteraceae | 8 |
| Ligusticum porteri | J.M.Coult. & Rose | Apiaceae | 8 |
| Lilium philadelphicum | L. | Liliaceae | 8 |
| Limonium limbatum | Small | Plumbaginaceae | 8 |
| Limosella aquatica | L. | Plantaginaceae | 8 |
| Linanthus pungens | (Torr.) J.M.Porter & L.A.Johnson | Polemoniaceae | 8 |
| Lindernia dubia | (L.) Pennell | Linderniaceae | 8 |
| Linnaea borealis | L. | Caprifoliaceae | 8 |
| Linum allredii | Sivinski & M.O.Howard | Linaceae | 8 |
| Linum aristatum | Engelm. | Linaceae | 8 |
| Linum australe | A.Heller | Linaceae | 8 |
| Linum berlandieri | Hook. | Linaceae | 8 |
| Linum compactum | A.Nelson | Linaceae | 8 |
| Linum hudsonioides | Planch. | 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 rigidum | Pursh | Linaceae | 8 |
| Linum rupestre | Engelm. ex A.Gray | Linaceae | 8 |
| Linum subteres | (Trel.) H.J.P.Winkl. | Linaceae | 8 |
| Linum vernale | Wooton | Linaceae | 8 |
| Lithophragma glabrum | Nutt. | Saxifragaceae | 8 |
| Lithophragma tenellum | Nutt. | Saxifragaceae | 8 |
| Lithospermum cobrense | Greene | Boraginaceae | 8 |
| Lithospermum incisum | Lehm. | Boraginaceae | 8 |
| Lithospermum mirabile | Small | Boraginaceae | 8 |
| Lithospermum multiflorum | Torr. ex A.Gray | Boraginaceae | 8 |
| Lithospermum occidentale | (Mack.) Weakley, Witsell & D.Estes | Boraginaceae | 8 |
| Lithospermum viride | Greene | Boraginaceae | 8 |
| Lobelia anatina | E.Wimm. | Campanulaceae | 8 |
| Lobelia cardinalis | L. | Campanulaceae | 8 |
| Lobelia fenestralis | Cav. | Campanulaceae | 8 |
| Loeflingia squarrosa | Nutt. | Caryophyllaceae | 8 |
| Lomatium foeniculaceum | (Nutt.) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium grayi | (J.M.Coult. & Rose) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium linearifolium | (S.Watson) J.F.Sm. & Mansfield | Apiaceae | 8 |
| Lomatium nevadense | (S.Watson) J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatium orientale | J.M.Coult. & Rose | Apiaceae | 8 |
| Lomatogonium rotatum | (L.) Fernald | Gentianaceae | 8 |
| Lonicera albiflora | Torr. & A.Gray | Caprifoliaceae | 8 |
| Lonicera arizonica | Rehder | Caprifoliaceae | 8 |
| Lonicera involucrata | (Richardson) Banks ex Spreng. | Caprifoliaceae | 8 |
| Lonicera utahensis | S.Watson | Caprifoliaceae | 8 |
| Lorandersonia baileyi | (Wooton & Standl.) Urbatsch, R.P.Roberts & Neubig | Asteraceae | 8 |
| Lorandersonia pulchella | (A.Gray) Urbatsch, R.P.Roberts & Neubig | Asteraceae | 8 |
| Ludwigia palustris | (L.) Elliott | Onagraceae | 8 |
| Ludwigia peploides | (Kunth) P.H.Raven | Onagraceae | 8 |
| Ludwigia repens | J.R.Forst. | Onagraceae | 8 |
| Lupinus ammophilus | Greene | Fabaceae | 8 |
| Lupinus argenteus | Pursh | 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 hillii | Greene | Fabaceae | 8 |
| Lupinus kingii | S.Watson | Fabaceae | 8 |
| Lupinus latifolius | Lindl. ex J.Agardh | Fabaceae | 8 |
| Lupinus neomexicanus | Greene | Fabaceae | 8 |
| Lupinus prunophilus | M.E.Jones | Fabaceae | 8 |
| Lupinus pusillus | Pursh | Fabaceae | 8 |
| Lupinus sierrae-blancae | Wooton & Standl. | 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 pallidum | Miers | Solanaceae | 8 |
| Lycium torreyi | A.Gray | Solanaceae | 8 |
| Lycopodium clavatum | L. | Lycopodiaceae | 8 |
| Lycopus americanus | Muhl. ex W.P.C.Barton | Lamiaceae | 8 |
| Lycopus asper | Greene | Lamiaceae | 8 |
| Lygodesmia juncea | (Pursh) Sweet | Asteraceae | 8 |
| Lygodesmia texana | (Torr. & A.Gray) Greene ex Small | Asteraceae | 8 |
| Lysimachia ciliata | L. | Primulaceae | 8 |
| Lysimachia hybrida | Michx. | Primulaceae | 8 |
| Lysimachia maritima | (L.) Galasso, Banfi & Soldano | Primulaceae | 8 |
| Lysimachia minima | (L.) U.Manns & Anderb. | Primulaceae | 8 |
| Lythrum californicum | Torr. & A.Gray | Lythraceae | 8 |
| Machaeranthera tagetina | Greene | Asteraceae | 8 |
| Machaeranthera tanacetifolia | (Kunth) Nees | Asteraceae | 8 |
| Macroptilium gibbosifolium | (Ortega) A.Delgado | Fabaceae | 8 |
| Madia glomerata | Hook. | Asteraceae | 8 |
| Maianthemum racemosum | (L.) Link | Asparagaceae | 8 |
| Maianthemum stellatum | (L.) Link | Asparagaceae | 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 |
| 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 |
| Mammillaria lasiacantha | Engelm. | Cactaceae | 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 macropoda | Engelm. ex A.Braun | Marsileaceae | 8 |
| Marsilea vestita | Hook. & Grev. | Marsileaceae | 8 |
| Matricaria discoidea | DC. | Asteraceae | 8 |
| Maurandella antirrhiniflora | (Humb. & Bonpl. ex Willd.) Rothm. | Plantaginaceae | 8 |
| Mecardonia procumbens | (Mill.) Small | Plantaginaceae | 8 |
| Melampodium leucanthum | Torr. & A.Gray | Asteraceae | 8 |
| Melica nitens | (Scribn.) Nutt. ex Piper | Poaceae | 8 |
| Menodora longiflora | Engelm. ex A.Gray | Oleaceae | 8 |
| Menodora scabra | Engelm. ex A.Gray | Oleaceae | 8 |
| Mentha canadensis | L. | Lamiaceae | 8 |
| Mentzelia albicaulis | (Douglas ex Hook.) Douglas ex Torr. & A.Gray | Loasaceae | 8 |
| Mentzelia decapetala | (Sims) Urb. | Loasaceae | 8 |
| Mentzelia humilis | (Urb. & Gilg) J.Darl. | Loasaceae | 8 |
| Mentzelia longiloba | J.Darl. | Loasaceae | 8 |
| Mentzelia montana | (Davidson) Davidson | Loasaceae | 8 |
| Mentzelia multiflora | (Nutt.) A.Gray | Loasaceae | 8 |
| Mentzelia nuda | (Pursh) Torr. & A.Gray | Loasaceae | 8 |
| Mentzelia oligosperma | Nutt. ex Sims | Loasaceae | 8 |
| Mentzelia procera | (Wooton & Standl.) J.J.Schenk & L.Hufford | Loasaceae | 8 |
| Mentzelia rusbyi | Wooton | Loasaceae | 8 |
| Mentzelia sivinskii | J.J.Schenk & L.Hufford | Loasaceae | 8 |
| Mentzelia strictissima | (Wooton & Standl.) J.Darl. | Loasaceae | 8 |
| Mentzelia todiltoensis | N.D.Atwood & S.L.Welsh | Loasaceae | 8 |
| Menyanthes trifoliata | L. | Menyanthaceae | 8 |
| Mertensia brevistyla | S.Watson | Boraginaceae | 8 |
| Mertensia ciliata | (E.James ex Torr.) G.Don | Boraginaceae | 8 |
| Mertensia fendleri | A.Gray | Boraginaceae | 8 |
| Mertensia franciscana | A.Heller | Boraginaceae | 8 |
| Mertensia lanceolata | (Pursh) DC. | Boraginaceae | 8 |
| Mertensia tweedyi | Rydb. | Boraginaceae | 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 |
| Mimosa aculeaticarpa | Ortega | Fabaceae | 8 |
| Mimosa biuncifera | Benth. | Fabaceae | 8 |
| Mimosa borealis | A.Gray | Fabaceae | 8 |
| Mimosa dysocarpa | Benth. | Fabaceae | 8 |
| Mimosa grahamii | A.Gray | Fabaceae | 8 |
| Mimosa nuttallii | (Raspail) B.L.Turner | Fabaceae | 8 |
| Mimosa texana | (A.Gray) Small | 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 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 |
| Moehringia lateriflora | (L.) Fenzl | Caryophyllaceae | 8 |
| Moehringia macrophylla | (Hook.) Fenzl | Caryophyllaceae | 8 |
| Mollugo verticillata | L. | Molluginaceae | 8 |
| Monarda citriodora | Cerv. ex Lag. | Lamiaceae | 8 |
| Monarda fistulosa | L. | Lamiaceae | 8 |
| Monarda humilis | (Torr.) Prather & J.A.Keith | Lamiaceae | 8 |
| Monarda pectinata | Nutt. | Lamiaceae | 8 |
| Monarda punctata | L. | Lamiaceae | 8 |
| Monardella odoratissima | Benth. | Lamiaceae | 8 |
| Moneses uniflora | (L.) A.Gray | Ericaceae | 8 |
| Monnina wrightii | A.Gray | Polygalaceae | 8 |
| Montia chamissoi | (Ledeb. ex Spreng.) Greene | Montiaceae | 8 |
| Mortonia scabrella | A.Gray | Celastraceae | 8 |
| Morus microphylla | Buckley | Moraceae | 8 |
| Mostacillastrum subauriculatum | Al-Shehbaz | Brassicaceae | 8 |
| Muenchhusia moscheutos | (L.) M.M.Hanes & R.L.Barrett | Malvaceae | 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 cuspidata | (Torr. ex Hook.) Rydb. | Poaceae | 8 |
| Muhlenbergia depauperata | Scribn. | Poaceae | 8 |
| Muhlenbergia emersleyi | Vasey | Poaceae | 8 |
| Muhlenbergia longiligula | Hitchc. | Poaceae | 8 |
| Muhlenbergia mexicana | (L.) 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 setifolia | Vasey | Poaceae | 8 |
| Muhlenbergia sinuosa | Swallen | Poaceae | 8 |
| Muhlenbergia spiciformis | Trin. | Poaceae | 8 |
| Muhlenbergia torreyi | (Kunth) Hitchc. ex Bush | Poaceae | 8 |
| Muhlenbergia tricholepis | (Torr.) P.M.Peterson | Poaceae | 8 |
| Muhlenbergia wrightii | Vasey ex J.M.Coult. | Poaceae | 8 |
| Munroa pulchella | (Kunth) Amarilla | Poaceae | 8 |
| Munroa squarrosa | (Nutt.) Torr. | Poaceae | 8 |
| Myriophyllum pinnatum | (Walter) Britton, Sterns & Poggenb. | 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 fendleri | Fourn. | Pteridaceae | 8 |
| Myriopteris lindheimeri | J.Sm. | 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 carnosa | (Wooton) C.L.Hitchc. | Namaceae | 8 |
| Nama dichotoma | (Ruiz & Pav.) Choisy | Namaceae | 8 |
| Nama hispida | A.Gray | Namaceae | 8 |
| Nama stevensii | C.L.Hitchc. | Namaceae | 8 |
| Nama xylopoda | (Wooton & Standl.) C.L.Hitchc. | Namaceae | 8 |
| Nassella tenuissima | (Trin.) Barkworth | Poaceae | 8 |
| Nassella viridula | (Trin.) Barkworth | Poaceae | 8 |
| Nekemias arborea | (L.) J.Wen & Boggan | Vitaceae | 8 |
| Neltuma glandulosa | (Torr.) Britton & Rose | Fabaceae | 8 |
| Neltuma odorata | (Torr. & Frém.) C.E.Hughes & G.P.Lewis | Fabaceae | 8 |
| Neltuma velutina | (Wooton) Britton & Rose | Fabaceae | 8 |
| Nemacladus orientalis | (McVaugh) Morin | Campanulaceae | 8 |
| Neokochia americana | (S.Watson) G.L.Chu & S.C.Sand. | Chenopodiaceae | 8 |
| Neottia borealis | (Morong) Szlach. | Orchidaceae | 8 |
| Neottia cordata | (L.) Rich. | Orchidaceae | 8 |
| Nerisyrenia camporum | (A.Gray) Greene | Brassicaceae | 8 |
| Nerisyrenia hypercorax | P.J.Alexander & M.J.Moore | Brassicaceae | 8 |
| Nerisyrenia linearifolia | Greene | Brassicaceae | 8 |
| Nicotiana attenuata | Torr. ex S.Watson | Solanaceae | 8 |
| Nicotiana obtusifolia | M.Martens & Galeotti | Solanaceae | 8 |
| Noccaea fendleri | (A.Gray) Holub | Brassicaceae | 8 |
| Nolina greenei | S.Watson ex Wooton & Standl. | Asparagaceae | 8 |
| Nolina micrantha | I.M.Johnst. | Asparagaceae | 8 |
| Nolina microcarpa | S.Watson | Asparagaceae | 8 |
| Nolina texana | S.Watson | Asparagaceae | 8 |
| Nothocalais cuspidata | (Pursh) Greene | Asteraceae | 8 |
| Nothoscordum bivalve | (L.) Britton | Amaryllidaceae | 8 |
| Nuphar polysepala | Engelm. | Nymphaeaceae | 8 |
| Nuttallanthus texanus | (Scheele) D.A.Sutton | Plantaginaceae | 8 |
| Nyctaginia capitata | Choisy | Nyctaginaceae | 8 |
| Oenothera albicaulis | Nutt. ex Pursh | Onagraceae | 8 |
| Oenothera brachycarpa | A.Gray | Onagraceae | 8 |
| Oenothera canescens | Torr. | Onagraceae | 8 |
| Oenothera capillifolia | Scheele | Onagraceae | 8 |
| Oenothera cespitosa | Nutt. | Onagraceae | 8 |
| Oenothera cinerea | (Wooton & Standl.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera coronopifolia | Torr. & A.Gray | Onagraceae | 8 |
| Oenothera curtiflora | W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera elata | Kunth | Onagraceae | 8 |
| Oenothera engelmannii | (Small) Munz | Onagraceae | 8 |
| Oenothera flava | (A.Nelson) Garrett | Onagraceae | 8 |
| Oenothera gayleana | B.L.Turner & M.J.Moore | Onagraceae | 8 |
| Oenothera glaucifolia | W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera grandis | Smyth | Onagraceae | 8 |
| Oenothera hartwegii | Benth. | Onagraceae | 8 |
| Oenothera laciniata | Hill | 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 rhombipetala | Nutt. ex Torr. & A.Gray | Onagraceae | 8 |
| Oenothera rosea | Aiton | Onagraceae | 8 |
| Oenothera serrulata | Nutt. | Onagraceae | 8 |
| Oenothera speciosa | Nutt. | Onagraceae | 8 |
| Oenothera suffrutescens | (Ser.) W.L.Wagner & Hoch | Onagraceae | 8 |
| Oenothera toumeyi | (Small) Tidestr. | Onagraceae | 8 |
| Oenothera triloba | Nutt. | Onagraceae | 8 |
| Oenothera tubicula | A.Gray | Onagraceae | 8 |
| Oenothera villosa | Thunb. | Onagraceae | 8 |
| Oligomeris linifolia | (Vahl ex Hornem.) J.F.Macbr. | Resedaceae | 8 |
| Ophioglossum engelmannii | Prantl | Ophioglossaceae | 8 |
| Opuntia arenaria | Engelm. | Cactaceae | 8 |
| Opuntia chlorotica | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Opuntia cymochila | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Opuntia engelmannii | Salm-Dyck ex Engelm. | Cactaceae | 8 |
| Opuntia fragilis | (Nutt.) Haw. | 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 polyacantha | Haw. | Cactaceae | 8 |
| Opuntia pottsii | Salm-Dyck | Cactaceae | 8 |
| Opuntia tortispina | Engelm. & J.M.Bigelow | Cactaceae | 8 |
| Oreocarya flava | A.Nelson | Boraginaceae | 8 |
| Oreocarya flavoculata | A.Nelson | Boraginaceae | 8 |
| Oreocarya fulvocanescens | (S.Watson) Greene | Boraginaceae | 8 |
| Oreocarya oblata | (M.E.Jones) J.F.Macbr. | Boraginaceae | 8 |
| Oreocarya palmeri | (A.Gray) Greene | Boraginaceae | 8 |
| Oreocarya setosissima | (A.Gray) Greene | Boraginaceae | 8 |
| Oreocarya suffruticosa | (Torr.) Greene | Boraginaceae | 8 |
| Oreocarya thyrsiflora | 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 ludoviciana | Nutt. | Orobanchaceae | 8 |
| Orobanche pinorum | Geyer ex Hook. | 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 |
| Oryzopsis asperifolia | Michx. | Poaceae | 8 |
| Osmorhiza berteroi | DC. | Apiaceae | 8 |
| Osmorhiza depauperata | Phil. | Apiaceae | 8 |
| Osmorhiza longistylis | DC. | Apiaceae | 8 |
| Ostrya knowltonii | Coville | Betulaceae | 8 |
| Oxalis caerulea | (Small) R.Knuth | Oxalidaceae | 8 |
| Oxalis decaphylla | Kunth | Oxalidaceae | 8 |
| Oxalis dillenii | Jacq. | Oxalidaceae | 8 |
| Oxalis frutescens | L. | 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 |
| Oxytropis deflexa | (Pall.) DC. | Fabaceae | 8 |
| Oxytropis lambertii | Pursh | Fabaceae | 8 |
| Oxytropis parryi | A.Gray | Fabaceae | 8 |
| Oxytropis sericea | Nutt. | Fabaceae | 8 |
| Oxytropis splendens | Douglas | Fabaceae | 8 |
| Packera cana | (Hook.) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera cynthioides | (Greene) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera dimorphophylla | (Greene) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera fendleri | (A.Gray) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera neomexicana | (A.Gray) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera plattensis | (Nutt.) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera pseudaurea | (Rydb.) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Packera streptanthifolia | (Greene) W.A.Weber & Á.Löve | Asteraceae | 8 |
| Palafoxia rosea | (Bush) Cory | Asteraceae | 8 |
| Palafoxia sphacelata | (Nutt. ex Torr.) Cory | Asteraceae | 8 |
| Panicum amarum | Elliott | Poaceae | 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 |
| Parnassia fimbriata | K.D.Koenig | Celastraceae | 8 |
| Parnassia palustris | L. | Celastraceae | 8 |
| Paronychia depressa | (Torr. & A.Gray) Nutt. ex A.Nelson | Caryophyllaceae | 8 |
| Paronychia jamesii | Torr. & A.Gray | Caryophyllaceae | 8 |
| Paronychia pulvinata | A.Gray | Caryophyllaceae | 8 |
| Paronychia sessiliflora | Nutt. | Caryophyllaceae | 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 |
| Paxistima myrsinites | (Pursh) Raf. | Celastraceae | 8 |
| Pectiantia pentandra | (Hook.) Rydb. | Saxifragaceae | 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 heterocarpa | (I.M.Johnst.) I.M.Johnst. | 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 bracteosa | Benth. | Orobanchaceae | 8 |
| Pedicularis canadensis | L. | Orobanchaceae | 8 |
| Pedicularis centranthera | A.Gray | Orobanchaceae | 8 |
| Pedicularis crenulata | Benth. | 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 simpsonii | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Pediomelum argophyllum | (Pursh) J.W.Grimes | Fabaceae | 8 |
| Pediomelum digitatum | (Nutt.) Isely | Fabaceae | 8 |
| Pediomelum esculentum | (Pursh) Rydb. | Fabaceae | 8 |
| Pediomelum hypogaeum | (Nutt.) Rydb. | Fabaceae | 8 |
| Pediomelum linearifolium | (Torr. & A.Gray) J.W.Grimes | Fabaceae | 8 |
| Pediomelum megalanthum | (Wooton & Standl.) Rydb. | Fabaceae | 8 |
| Pediomelum pentaphyllum | (L.) Rydb. | Fabaceae | 8 |
| Pediomelum tenuiflorum | (Pursh) A.N.Egan | Fabaceae | 8 |
| Pelecyphora macromeris | (Engelm.) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pelecyphora missouriensis | (Sweet) D.Aquino & Dan.Sánchez | Cactaceae | 8 |
| Pelecyphora tuberculosa | (Engelm.) 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 truncata | Goodd. | Pteridaceae | 8 |
| Pellaea wrightiana | Hook. | Pteridaceae | 8 |
| Peniocereus greggii | (Engelm.) Britton & Rose | Cactaceae | 8 |
| Pennellia longifolia | (Benth.) Rollins | Brassicaceae | 8 |
| Pennellia micrantha | (A.Gray) Nieuwl. | Brassicaceae | 8 |
| Penstemon albidus | Nutt. | Plantaginaceae | 8 |
| Penstemon ambiguus | Torr. | Plantaginaceae | 8 |
| Penstemon angustifolius | Nutt. ex Pursh | Plantaginaceae | 8 |
| Penstemon barbatus | (Cav.) Roth | Plantaginaceae | 8 |
| Penstemon bradburyi | Pursh | Plantaginaceae | 8 |
| Penstemon breviculus | (D.D.Keck) G.T.Nisbet & R.C.Jacks. | Plantaginaceae | 8 |
| Penstemon buckleyi | Pennell | Plantaginaceae | 8 |
| Penstemon comarrhenus | A.Gray | Plantaginaceae | 8 |
| Penstemon crandallii | A.Nelson | Plantaginaceae | 8 |
| Penstemon dasyphyllus | A.Gray | Plantaginaceae | 8 |
| Penstemon eatonii | A.Gray | Plantaginaceae | 8 |
| Penstemon fendleri | Torr. & A.Gray | Plantaginaceae | 8 |
| Penstemon glaber | Pursh | Plantaginaceae | 8 |
| Penstemon gracilis | Nutt. | Plantaginaceae | 8 |
| Penstemon jamesii | Benth. | Plantaginaceae | 8 |
| Penstemon lanceolatus | Benth. | Plantaginaceae | 8 |
| Penstemon linarioides | A.Gray | Plantaginaceae | 8 |
| Penstemon neomexicanus | Wooton & Standl. | Plantaginaceae | 8 |
| Penstemon oliganthus | Wooton & Standl. | Plantaginaceae | 8 |
| Penstemon ophianthus | Pennell | Plantaginaceae | 8 |
| Penstemon palmeri | A.Gray | Plantaginaceae | 8 |
| Penstemon pinifolius | Greene | Plantaginaceae | 8 |
| Penstemon pseudospectabilis | M.E.Jones | Plantaginaceae | 8 |
| Penstemon rostriflorus | Kellogg | Plantaginaceae | 8 |
| Penstemon rydbergii | A.Nelson | Plantaginaceae | 8 |
| Penstemon secundiflorus | Benth. | Plantaginaceae | 8 |
| Penstemon strictus | Benth. | Plantaginaceae | 8 |
| Penstemon superbus | A.Nelson | Plantaginaceae | 8 |
| Penstemon thurberi | Torr. | Plantaginaceae | 8 |
| Penstemon virgatus | A.Gray | Plantaginaceae | 8 |
| Penstemon whippleanus | A.Gray | Plantaginaceae | 8 |
| Peraphyllum ramosissimum | Nutt. | Rosaceae | 8 |
| Pericome caudata | A.Gray | Asteraceae | 8 |
| Perityle lemmonii | (A.Gray) J.F.Macbr. | Asteraceae | 8 |
| Perityle quinqueflora | (Steyerm.) Shinners | Asteraceae | 8 |
| Perityle staurophylla | (Barneby) Shinners | Asteraceae | 8 |
| Persicaria amphibia | (L.) Delarbre | Polygonaceae | 8 |
| Persicaria bicornis | (Raf.) Nieuwl. | 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 |
| Peteria scoparia | A.Gray | Fabaceae | 8 |
| Petradoria pumila | (Nutt.) Greene | Asteraceae | 8 |
| Petrophytum caespitosum | (Nutt.) Rydb. | Rosaceae | 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 coerulea | Greene | Hydrophyllaceae | 8 |
| Phacelia congesta | Hook. | Hydrophyllaceae | 8 |
| Phacelia crenulata | Torr. ex S.Watson | Hydrophyllaceae | 8 |
| Phacelia cryptantha | Greene | Hydrophyllaceae | 8 |
| Phacelia heterophylla | Pursh | Hydrophyllaceae | 8 |
| Phacelia integrifolia | Torr. | Hydrophyllaceae | 8 |
| Phacelia ivesiana | Torr. | Hydrophyllaceae | 8 |
| Phacelia popei | Torr. & A.Gray | Hydrophyllaceae | 8 |
| Phacelia rupestris | Greene | Hydrophyllaceae | 8 |
| Phacelia sericea | (Graham) A.Gray | Hydrophyllaceae | 8 |
| Phacelia sivinskii | N.D.Atwood, P.J.Knight & Lowrey | 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 calcaricus | (S.Ware) Kiger | Montiaceae | 8 |
| Phemeranthus calycinus | (Engelm.) Kiger | Montiaceae | 8 |
| Phemeranthus parviflorus | (Nutt.) Kiger | Montiaceae | 8 |
| Philadelphus microphyllus | A.Gray | Hydrangeaceae | 8 |
| Phleum alpinum | L. | Poaceae | 8 |
| Phlox austromontana | Coville | Polemoniaceae | 8 |
| Phlox condensata | (A.Gray) E.E.Nelson | Polemoniaceae | 8 |
| Phlox hoodii | Richardson | Polemoniaceae | 8 |
| Phlox longifolia | Nutt. | Polemoniaceae | 8 |
| Phlox multiflora | A.Nelson | Polemoniaceae | 8 |
| Phlox nana | Nutt. | Polemoniaceae | 8 |
| Phlox pulvinata | (Wherry) Cronquist | Polemoniaceae | 8 |
| Phlox woodhousei | (A.Gray) E.E.Nelson | Polemoniaceae | 8 |
| Phoradendron californicum | Nutt. | Santalaceae | 8 |
| Phoradendron capitellatum | Torr. ex Trel. | Santalaceae | 8 |
| Phoradendron coryae | Trel. | Santalaceae | 8 |
| Phoradendron hawksworthii | Wiens | Santalaceae | 8 |
| Phoradendron juniperinum | Engelm. ex A.Gray | Santalaceae | 8 |
| Phoradendron macrophyllum | (Engelm.) Cockerell | 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 abnormis | Baill. | Phyllanthaceae | 8 |
| Phyllanthus polygonoides | Nutt. ex Spreng. | Phyllanthaceae | 8 |
| Phyllanthus warnockii | G.L.Webster | Phyllanthaceae | 8 |
| Physalis acutifolia | (Miers) Sandwith | Solanaceae | 8 |
| Physalis angulata | L. | 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 |
| Physalis virginiana | Mill. | Solanaceae | 8 |
| Physaria acutifolia | Rydb. | Brassicaceae | 8 |
| Physaria fendleri | (A.Gray) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria gordonii | (A.Gray) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria ludoviciana | (Nutt.) O'Kane & Al-Shehbaz | Brassicaceae | 8 |
| Physaria montana | (A.Gray) Greene | Brassicaceae | 8 |
| Physaria ovalifolia | (Rydb.) O'Kane & Al-Shehbaz | 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 |
| Physostegia virginiana | (L.) Benth. | Lamiaceae | 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 |
| 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 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 |
| Plagiobothrys arizonicus | (A.Gray) Greene ex A.Gray | Boraginaceae | 8 |
| Plagiobothrys scouleri | (Hook. & Arn.) I.M.Johnst. | Boraginaceae | 8 |
| Plantago aristata | Michx. | Plantaginaceae | 8 |
| Plantago elongata | Pursh | Plantaginaceae | 8 |
| Plantago helleri | Small | Plantaginaceae | 8 |
| Plantago patagonica | Jacq. | Plantaginaceae | 8 |
| Plantago rhodosperma | Decne. | Plantaginaceae | 8 |
| Plantago virginica | L. | Plantaginaceae | 8 |
| Plantago wrightiana | Decne. | Plantaginaceae | 8 |
| Platanthera aquilonis | Sheviak | Orchidaceae | 8 |
| Platanthera brevifolia | (Greene) Senghas | Orchidaceae | 8 |
| Platanthera dilatata | (Pursh) Lindl. ex L.C.Beck | Orchidaceae | 8 |
| Platanthera huronensis | Lindl. | Orchidaceae | 8 |
| Platanthera obtusata | (Banks ex Pursh) Lindl. | Orchidaceae | 8 |
| Platanthera purpurascens | (Rydb.) Sheviak & W.F.Jenn. | Orchidaceae | 8 |
| Platanthera sparsiflora | (S.Watson) Schltr. | Orchidaceae | 8 |
| Platanthera unalascensis | (Spreng.) Kurtz | Orchidaceae | 8 |
| Platanus wrightii | S.Watson | Platanaceae | 8 |
| Platyschkuhria integrifolia | (A.Gray) Rydb. | Asteraceae | 8 |
| Pluchea odorata | (L.) Cass. | Asteraceae | 8 |
| Pluchea sericea | (Nutt.) Coville | Asteraceae | 8 |
| Poa alpina | L. | Poaceae | 8 |
| Poa arachnifera | Torr. | Poaceae | 8 |
| Poa arctica | R.Br. | Poaceae | 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 palustris | L. | Poaceae | 8 |
| Poa pratensis | L. | Poaceae | 8 |
| Poa secunda | J.Presl | Poaceae | 8 |
| Poa wheeleri | Vasey | Poaceae | 8 |
| Podistera eastwoodiae | (J.M.Coult. & Rose) Mathias & Constance | Apiaceae | 8 |
| Polemonium foliosissimum | A.Gray | Polemoniaceae | 8 |
| Polemonium occidentale | Greene | 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 |
| Pomaria jamesii | (Torr. & A.Gray) Walp. | Fabaceae | 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 |
| Porophyllum scoparium | A.Gray | Asteraceae | 8 |
| Portulaca halimoides | L. | Portulacaceae | 8 |
| Portulaca pilosa | L. | Portulacaceae | 8 |
| Portulaca suffrutescens | Engelm. | Portulacaceae | 8 |
| Portulaca umbraticola | Kunth | Portulacaceae | 8 |
| Potamogeton alpinus | Balb. | Potamogetonaceae | 8 |
| Potamogeton diversifolius | Raf. | Potamogetonaceae | 8 |
| Potamogeton foliosus | Raf. | Potamogetonaceae | 8 |
| Potamogeton gramineus | L. | Potamogetonaceae | 8 |
| Potamogeton illinoensis | Morong | Potamogetonaceae | 8 |
| Potamogeton natans | L. | Potamogetonaceae | 8 |
| Potamogeton nodosus | Poir. | Potamogetonaceae | 8 |
| Potamogeton pusillus | L. | Potamogetonaceae | 8 |
| Potamogeton richardsonii | Rydb. | Potamogetonaceae | 8 |
| Potentilla bicrenata | Rydb. | 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 supina | L. | Rosaceae | 8 |
| Potentilla thurberi | A.Gray | Rosaceae | 8 |
| Primula angustifolia | Torr. | Primulaceae | 8 |
| Primula parryi | A.Gray | Primulaceae | 8 |
| Primula pauciflora | (Greene) A.R.Mast & Reveal | Primulaceae | 8 |
| Primula rusbyi | Greene | Primulaceae | 8 |
| Proatriplex pleiantha | (W.A.Weber) Stutz & G.L.Chu | Chenopodiaceae | 8 |
| Proboscidea althaeifolia | (Benth.) Decne. | Martyniaceae | 8 |
| Proboscidea louisianica | (Mill.) Thell. | Martyniaceae | 8 |
| Proboscidea parviflora | (Wooton) Wooton & Standl. | Martyniaceae | 8 |
| Proboscidea sabulosa | Correll | Martyniaceae | 8 |
| Prosartes trachycarpa | S.Watson | Liliaceae | 8 |
| Prunella vulgaris | L. | Lamiaceae | 8 |
| Prunus americana | Marshall | Rosaceae | 8 |
| Prunus angustifolia | Marshall | Rosaceae | 8 |
| Prunus emarginata | (Douglas ex Hook.) Eaton | Rosaceae | 8 |
| Prunus gracilis | Engelm. & A.Gray | Rosaceae | 8 |
| Prunus serotina | Ehrh. | Rosaceae | 8 |
| Prunus virginiana | L. | Rosaceae | 8 |
| Psacalium decompositum | (A.Gray) H.Rob. & Brettell | Asteraceae | 8 |
| Psathyrotopsis scaposa | (A.Gray) H.Rob. | 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 |
| Pseudotsuga menziesii | (Mirb.) Franco | Pinaceae | 8 |
| Psilactis asteroides | A.Gray | Asteraceae | 8 |
| Psilostrophe sparsiflora | (A.Gray) A.Nelson | Asteraceae | 8 |
| Psilostrophe tagetina | (Nutt.) Greene | Asteraceae | 8 |
| Psilostrophe villosa | Rydb. ex Britton | Asteraceae | 8 |
| Psorothamnus scoparius | (A.Gray) Rydb. | Fabaceae | 8 |
| Ptelea trifoliata | L. | Rutaceae | 8 |
| Pteridium aquilinum | (L.) Kuhn | Dennstaedtiaceae | 8 |
| Pterospora andromedea | Nutt. | Ericaceae | 8 |
| Puccinellia nuttalliana | (Schult.) Hitchc. | Poaceae | 8 |
| Pulsatilla nuttalliana | (DC.) Spreng. | Ranunculaceae | 8 |
| Purshia stansburyana | (Torr.) Henrickson | Rosaceae | 8 |
| Purshia tridentata | (Pursh) DC. | Rosaceae | 8 |
| Pyrola asarifolia | Michx. | Ericaceae | 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 havardii | Rydb. | Fagaceae | 8 |
| Quercus hypoleucoides | A.Camus | Fagaceae | 8 |
| Quercus mohriana | Buckley ex Rydb. | Fagaceae | 8 |
| Quercus muehlenbergii | Engelm. | Fagaceae | 8 |
| Quercus oblongifolia | Torr. | 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 neomexicana | A.Gray | Asteraceae | 8 |
| Ranunculus abortivus | L. | Ranunculaceae | 8 |
| Ranunculus alismifolius | Geyer ex Benth. | Ranunculaceae | 8 |
| Ranunculus cardiophyllus | Hook. | Ranunculaceae | 8 |
| Ranunculus eschscholtzii | Schltdl. | Ranunculaceae | 8 |
| Ranunculus flammula | L. | Ranunculaceae | 8 |
| Ranunculus glaberrimus | Hook. | Ranunculaceae | 8 |
| Ranunculus gmelinii | DC. | Ranunculaceae | 8 |
| Ranunculus inamoenus | Greene | Ranunculaceae | 8 |
| Ranunculus longirostris | Godr. | Ranunculaceae | 8 |
| Ranunculus macauleyi | A.Gray | Ranunculaceae | 8 |
| Ranunculus macounii | Britton | Ranunculaceae | 8 |
| Ranunculus minimus | E.H.L.Krause | Ranunculaceae | 8 |
| Ranunculus pensylvanicus | L.f. | Ranunculaceae | 8 |
| Ranunculus sceleratus | L. | 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 |
| Rhinotropis lindheimeri | (A.Gray) J.R.Abbott | Polygalaceae | 8 |
| Rhinotropis subspinosa | (S.Watson) J.R.Abbott | Polygalaceae | 8 |
| Rhodiola integrifolia | Raf. | Crassulaceae | 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 virens | Lindh. ex A.Gray | Anacardiaceae | 8 |
| Rhynchosia senna | Gillies ex Hook. & Arn. | Fabaceae | 8 |
| Rhynchosida physocalyx | (A.Gray) Fryxell | Malvaceae | 8 |
| Ribes americanum | Mill. | Grossulariaceae | 8 |
| Ribes aureum | Pursh | Grossulariaceae | 8 |
| Ribes cereum | Douglas | Grossulariaceae | 8 |
| Ribes inerme | Rydb. | Grossulariaceae | 8 |
| Ribes lacustre | (Pers.) Poir. | Grossulariaceae | 8 |
| Ribes laxiflorum | Pursh | Grossulariaceae | 8 |
| Ribes leptanthum | A.Gray | Grossulariaceae | 8 |
| Ribes mescalerium | Coville | Grossulariaceae | 8 |
| Ribes montigenum | McClatchie | Grossulariaceae | 8 |
| Ribes pinetorum | 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 |
| Rorippa teres | (Michx.) Stuckey | Brassicaceae | 8 |
| Rosa acicularis | Lindl. | Rosaceae | 8 |
| Rosa arkansana | Porter | Rosaceae | 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 amplexicaulis | Vahl | Asteraceae | 8 |
| Rudbeckia hirta | L. | Asteraceae | 8 |
| Rudbeckia laciniata | L. | Asteraceae | 8 |
| Ruellia parryi | A.Gray | Acanthaceae | 8 |
| Rumex altissimus | Alph.Wood | Polygonaceae | 8 |
| Rumex californicus | Rech.f. | Polygonaceae | 8 |
| Rumex hastatulus | Baldwin | Polygonaceae | 8 |
| Rumex hymenosepalus | Torr. | Polygonaceae | 8 |
| Rumex maritimus | L. | Polygonaceae | 8 |
| Rumex occidentalis | S.Watson | Polygonaceae | 8 |
| Rumex triangulivalvis | (Danser) Rech.f. | Polygonaceae | 8 |
| Rumex venosus | Pursh | Polygonaceae | 8 |
| Ruppia cirrhosa | (Petagna) Grande | Ruppiaceae | 8 |
| Sabulina michauxii | (Fenzl) Dillenb. & Kadereit | Caryophyllaceae | 8 |
| Sabulina rubella | (Wahlenb.) Dillenb. & Kadereit | Caryophyllaceae | 8 |
| Sagina saginoides | (L.) H.Karst. | Caryophyllaceae | 8 |
| Sagittaria brevirostra | Mack. & Bush | Alismataceae | 8 |
| Sagittaria cuneata | E.Sheld. | Alismataceae | 8 |
| Sagittaria graminea | Michx. | Alismataceae | 8 |
| Sagittaria latifolia | Willd. | Alismataceae | 8 |
| Sagittaria longiloba | Engelm. ex J.G.Sm. | Alismataceae | 8 |
| Sagittaria montevidensis | Cham. & Schltdl. | Alismataceae | 8 |
| Salicornia rubra | A.Nelson | Chenopodiaceae | 8 |
| Salix amygdaloides | Andersson | Salicaceae | 8 |
| Salix bebbiana | Sarg. | Salicaceae | 8 |
| Salix bonplandiana | Kunth | Salicaceae | 8 |
| Salix boothii | Dorn | Salicaceae | 8 |
| Salix brachycarpa | Nutt. | Salicaceae | 8 |
| Salix drummondiana | Barratt | Salicaceae | 8 |
| Salix exigua | Nutt. | Salicaceae | 8 |
| Salix geyeriana | Andersson | Salicaceae | 8 |
| Salix glauca | L. | Salicaceae | 8 |
| Salix gooddingii | C.R.Ball | Salicaceae | 8 |
| Salix interior | Rowlee | Salicaceae | 8 |
| Salix laevigata | Bebb | Salicaceae | 8 |
| Salix lasiandra | Benth. | Salicaceae | 8 |
| Salix lasiolepis | Benth. | Salicaceae | 8 |
| Salix nigra | Marshall | Salicaceae | 8 |
| Salix nivalis | Hook. | Salicaceae | 8 |
| Salix petrophila | Rydb. | Salicaceae | 8 |
| Salix planifolia | Pursh | Salicaceae | 8 |
| Salix scouleriana | Barratt | Salicaceae | 8 |
| Salix taxifolia | Kunth | Salicaceae | 8 |
| Salix wolfii | Bebb | Salicaceae | 8 |
| Salvia azurea | Lam. ex Vahl | Lamiaceae | 8 |
| Salvia columbariae | Benth. | Lamiaceae | 8 |
| Salvia farinacea | Benth. | Lamiaceae | 8 |
| Salvia henryi | A.Gray | Lamiaceae | 8 |
| Salvia lycioides | A.Gray | Lamiaceae | 8 |
| Salvia pinguifolia | (Fernald) Wooton & Standl. | Lamiaceae | 8 |
| Salvia reflexa | Hornem. | Lamiaceae | 8 |
| Salvia subincisa | Benth. | Lamiaceae | 8 |
| Salvia texana | (Scheele) Torr. | Lamiaceae | 8 |
| Sambucus canadensis | L. | Viburnaceae | 8 |
| Sambucus cerulea | Raf. | Viburnaceae | 8 |
| Sambucus racemosa | L. | Viburnaceae | 8 |
| Samolus ebracteatus | Kunth | Primulaceae | 8 |
| Samolus parviflorus | Raf. | Primulaceae | 8 |
| Sanguisorba occidentalis | Nutt. | Rosaceae | 8 |
| Sanicula marilandica | L. | Apiaceae | 8 |
| Sapindus drummondii | Hook. & Arn. | Sapindaceae | 8 |
| Sarcobatus vermiculatus | (Hook.) Torr. | Sarcobataceae | 8 |
| Sartwellia flaveriae | A.Gray | Asteraceae | 8 |
| Saxifraga bronchialis | L. | Saxifragaceae | 8 |
| Saxifraga cernua | L. | Saxifragaceae | 8 |
| Saxifraga cespitosa | L. | Saxifragaceae | 8 |
| Saxifraga chrysantha | A.Gray | Saxifragaceae | 8 |
| Saxifraga flagellaris | Willd. ex Sternb. | Saxifragaceae | 8 |
| Saxifraga hirculus | L. | Saxifragaceae | 8 |
| Schistophragma intermedium | (A.Gray) Pennell | Plantaginaceae | 8 |
| Schizachne purpurascens | (Torr.) Swallen | Poaceae | 8 |
| Schizachyrium sanguineum | (Retz.) Alston | Poaceae | 8 |
| Schizachyrium scoparium | (Michx.) Nash | Poaceae | 8 |
| Schkuhria pinnata | (Lam.) Kuntze ex Thell. | Asteraceae | 8 |
| Schoenocaulon texanum | Scheele | Melanthiaceae | 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 |
| Schoenus nigricans | L. | Cyperaceae | 8 |
| Scirpus microcarpus | J.Presl & C.Presl | Cyperaceae | 8 |
| Scirpus pendulus | Muhl. | Cyperaceae | 8 |
| Sclerocactus cloverae | K.D.Heil & J.M.Porter | Cactaceae | 8 |
| Sclerocactus intertextus | (Engelm.) N.P.Taylor | Cactaceae | 8 |
| Sclerocactus mesae-verdae | (Boissev. & C.Davidson) L.D.Benson | Cactaceae | 8 |
| Sclerocactus papyracanthus | (Engelm.) N.P.Taylor | Cactaceae | 8 |
| Sclerocactus parviflorus | Clover & Jotter | Cactaceae | 8 |
| Scleropogon brevifolius | Phil. | Poaceae | 8 |
| Scrophularia lanceolata | Pursh | Scrophulariaceae | 8 |
| Scrophularia montana | Wooton | Scrophulariaceae | 8 |
| Scrophularia parviflora | Wooton & Standl. | Scrophulariaceae | 8 |
| Scutellaria brittonii | Porter | Lamiaceae | 8 |
| Scutellaria drummondii | Benth. | Lamiaceae | 8 |
| Scutellaria galericulata | L. | Lamiaceae | 8 |
| Scutellaria lateriflora | L. | Lamiaceae | 8 |
| Scutellaria potosina | Brandegee | Lamiaceae | 8 |
| Sedum cockerellii | Britton | Crassulaceae | 8 |
| Sedum debile | S.Watson | Crassulaceae | 8 |
| Sedum lanceolatum | Torr. | Crassulaceae | 8 |
| Sedum stelliforme | S.Watson | Crassulaceae | 8 |
| Sedum wrightii | A.Gray | Crassulaceae | 8 |
| Selaginella arizonica | Maxon | Selaginellaceae | 8 |
| Selaginella lepidophylla | (Hook. & Grev.) Spring | Selaginellaceae | 8 |
| Selaginella longipila | Hieron. | Selaginellaceae | 8 |
| Selaginella mutica | D.C.Eaton | Selaginellaceae | 8 |
| Selaginella peruviana | Hieron. | Selaginellaceae | 8 |
| Selaginella pilifera | A.Br. | Selaginellaceae | 8 |
| Selaginella rupincola | Underw. | Selaginellaceae | 8 |
| Selaginella scopulorum | Maxon | Selaginellaceae | 8 |
| Selaginella underwoodii | Hieron. | Selaginellaceae | 8 |
| Selaginella watsonii | Underw. | Selaginellaceae | 8 |
| Selaginella wrightii | Hieron. | Selaginellaceae | 8 |
| Senecio amplectens | A.Gray | Asteraceae | 8 |
| Senecio atratus | Greene | Asteraceae | 8 |
| Senecio bigelovii | A.Gray | Asteraceae | 8 |
| Senecio crassulus | A.Gray | Asteraceae | 8 |
| Senecio eremophilus | Richardson | Asteraceae | 8 |
| Senecio flaccidus | Less. | Asteraceae | 8 |
| Senecio fremontii | Torr. & A.Gray | Asteraceae | 8 |
| Senecio integerrimus | Nutt. | Asteraceae | 8 |
| Senecio pudicus | Greene | Asteraceae | 8 |
| Senecio soldanella | A.Gray | Asteraceae | 8 |
| Senecio spartioides | Torr. & A.Gray | Asteraceae | 8 |
| Senecio taraxacoides | (A.Gray) Greene | Asteraceae | 8 |
| Senecio triangularis | Hook. | Asteraceae | 8 |
| Senecio warnockii | Shinners | Asteraceae | 8 |
| Senecio wootonii | Greene | Asteraceae | 8 |
| Senegalia greggii | (A.Gray) Britton & Rose | Fabaceae | 8 |
| Senegalia roemeriana | (Scheele) Britton & Rose | 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 roemeriana | (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 magna | Griseb. | Poaceae | 8 |
| Setaria parviflora | (Poir.) Kerguélen | Poaceae | 8 |
| Setaria reverchonii | (Vasey) Pilg. | Poaceae | 8 |
| Shepherdia argentea | (Pursh) Nutt. | Elaeagnaceae | 8 |
| Shepherdia canadensis | (L.) Nutt. | Elaeagnaceae | 8 |
| Sibbaldia procumbens | L. | Rosaceae | 8 |
| Sicyos glaber | Wooton | Cucurbitaceae | 8 |
| Sicyos laciniatus | L. | Cucurbitaceae | 8 |
| Sicyos microphyllus | Kunth | Cucurbitaceae | 8 |
| Sidalcea candida | A.Gray | Malvaceae | 8 |
| Sidalcea neomexicana | A.Gray | Malvaceae | 8 |
| Sideroxylon lanuginosum | Michx. | Sapotaceae | 8 |
| Sidneya tenuifolia | (A.Gray) E.E.Schill. & Panero | Asteraceae | 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 |
| Silphium integrifolium | Michx. | Asteraceae | 8 |
| Silphium laciniatum | L. | Asteraceae | 8 |
| Simmondsia chinensis | (Link) C.K.Schneid. | Simmondsiaceae | 8 |
| Simsia calva | A.Gray | Asteraceae | 8 |
| Sisyrinchium demissum | Greene | Iridaceae | 8 |
| Sisyrinchium ensigerum | E.P.Bicknell | Iridaceae | 8 |
| Sisyrinchium idahoense | E.P.Bicknell | Iridaceae | 8 |
| Sisyrinchium montanum | Greene | Iridaceae | 8 |
| Sium suave | Walter | Apiaceae | 8 |
| Solanum dimidiatum | Raf. | Solanaceae | 8 |
| Solanum douglasii | Dunal | Solanaceae | 8 |
| Solanum elaeagnifolium | Cav. | Solanaceae | 8 |
| Solanum emulans | Raf. | Solanaceae | 8 |
| Solanum heterodoxum | Dunal | Solanaceae | 8 |
| Solanum jamesii | Torr. | Solanaceae | 8 |
| Solanum nigrescens | M.Martens & Galeotti | Solanaceae | 8 |
| Solanum rostratum | Dunal | Solanaceae | 8 |
| Solanum stoloniferum | Schltdl. | Solanaceae | 8 |
| Solanum triflorum | Nutt. | Solanaceae | 8 |
| Solidago altissima | L. | Asteraceae | 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 petiolaris | Aiton | Asteraceae | 8 |
| Solidago rigida | L. | 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 |
| Spermolepis inermis | (Nutt. ex DC.) Mathias & Constance | Apiaceae | 8 |
| Spermolepis lateriflora | G.L.Nesom | Apiaceae | 8 |
| Sphaeralcea coccinea | (Nutt.) Rydb. | 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 |
| 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 magnicamporum | Sheviak | Orchidaceae | 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 heterolepis | (A.Gray) A.Gray | Poaceae | 8 |
| Sporobolus hookerianus | P.M.Peterson & Saarela | Poaceae | 8 |
| Sporobolus michauxianus | (Hitchc.) P.M.Peterson & Saarela | Poaceae | 8 |
| Sporobolus nealleyi | Vasey | Poaceae | 8 |
| Sporobolus neglectus | Nash | Poaceae | 8 |
| Sporobolus pyramidatus | (Lam.) Hitchc. | Poaceae | 8 |
| Sporobolus rigidus | (Buckley) P.M.Peterson | 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 pinnata | (Pursh) Britton | Brassicaceae | 8 |
| Stanleya viridiflora | Nutt. | Brassicaceae | 8 |
| Steinchisma hians | (Elliott) Nash | Poaceae | 8 |
| Stellaria crassifolia | Ehrh. | Caryophyllaceae | 8 |
| Stellaria cuspidata | D.F.K.Schltdl. | Caryophyllaceae | 8 |
| Stellaria longifolia | Muhl. ex Willd. | Caryophyllaceae | 8 |
| Stellaria longipes | Goldie | Caryophyllaceae | 8 |
| Stellaria nitens | Nutt. | Caryophyllaceae | 8 |
| Stenandrium barbatum | Torr. & A.Gray | Acanthaceae | 8 |
| Stenaria nigricans | (Lam.) Terrell | Rubiaceae | 8 |
| Stenogonum salsuginosum | Nutt. | Polygonaceae | 8 |
| Stenotus armerioides | Nutt. | Asteraceae | 8 |
| Stephanomeria exigua | Nutt. | Asteraceae | 8 |
| Stephanomeria pauciflora | (Torr.) A.Nelson | Asteraceae | 8 |
| Stephanomeria thurberi | A.Gray | Asteraceae | 8 |
| Stevia plummerae | A.Gray | Asteraceae | 8 |
| Stevia salicifolia | Cav. | Asteraceae | 8 |
| Stevia serrata | Cav. | Asteraceae | 8 |
| Stillingia sylvatica | L. | Euphorbiaceae | 8 |
| Streptanthus carinatus | Wright ex A.Gray | Brassicaceae | 8 |
| Streptanthus cordatus | Nutt. | Brassicaceae | 8 |
| Streptanthus lasiophyllus | Hook. & Arn. ex Hoover | Brassicaceae | 8 |
| Streptanthus longirostris | (S.Watson) S.Watson | Brassicaceae | 8 |
| Streptanthus platycarpus | A.Gray | Brassicaceae | 8 |
| Streptopus amplexifolius | (L.) DC. | Liliaceae | 8 |
| Strombocarpa pubescens | (Benth.) A.Gray | Fabaceae | 8 |
| Strophostyles leiosperma | (Torr. & A.Gray) Piper | Fabaceae | 8 |
| Stuckenia filiformis | (Pers.) Börner | Potamogetonaceae | 8 |
| Stuckenia pectinata | (L.) Börner | Potamogetonaceae | 8 |
| Stylocline micropoides | A.Gray | Asteraceae | 8 |
| Suaeda calceoliformis | (Hook.) Moq. | Chenopodiaceae | 8 |
| Suaeda nigra | (Raf.) J.F.Macbr. | Chenopodiaceae | 8 |
| Swertia perennis | L. | Gentianaceae | 8 |
| Symphoricarpos albus | (L.) S.F.Blake | Caprifoliaceae | 8 |
| Symphoricarpos longiflorus | A.Gray | Caprifoliaceae | 8 |
| Symphoricarpos occidentalis | (R.Br.) Hook. | 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 fendleri | (A.Gray) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum foliaceum | (Lindl. ex DC.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum frondosum | (Nutt.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum laeve | (L.) Á.Löve & D.Löve | Asteraceae | 8 |
| Symphyotrichum lanceolatum | (Willd.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum novae-angliae | (L.) G.L.Nesom | Asteraceae | 8 |
| Symphyotrichum oblongifolium | (Nutt.) G.L.Nesom | Asteraceae | 8 |
| Tagetes micrantha | Cav. | Asteraceae | 8 |
| Talinopsis frutescens | A.Gray | Anacampserotaceae | 8 |
| Talinum aurantiacum | Engelm. | Talinaceae | 8 |
| Talinum paniculatum | (Jacq.) Gaertn. | Talinaceae | 8 |
| Talinum polygaloides | Gillies ex Arn. | Talinaceae | 8 |
| Tecoma stans | (L.) Juss. | Bignoniaceae | 8 |
| Telesonix jamesii | Raf. | Saxifragaceae | 8 |
| Tetraclea coulteri | A.Gray | Lamiaceae | 8 |
| Tetradymia canescens | DC. | Asteraceae | 8 |
| Tetradymia filifolia | Greene | Asteraceae | 8 |
| Tetradymia spinosa | Hook. & Arn. | Asteraceae | 8 |
| Tetramerium nervosum | Nees | Acanthaceae | 8 |
| Tetraneuris acaulis | Greene | Asteraceae | 8 |
| Tetraneuris argentea | Greene | Asteraceae | 8 |
| Tetraneuris ivesiana | Greene | Asteraceae | 8 |
| Tetraneuris linearifolia | Greene | Asteraceae | 8 |
| Tetraneuris scaposa | (DC.) Greene | Asteraceae | 8 |
| Teucrium canadense | L. | Lamiaceae | 8 |
| Teucrium depressum | Small | Lamiaceae | 8 |
| Teucrium laciniatum | Torr. | Lamiaceae | 8 |
| Thalictrum alpinum | L. | Ranunculaceae | 8 |
| Thalictrum dasycarpum | Fisch., C.A.Mey. & Avé-Lall. | Ranunculaceae | 8 |
| Thalictrum fendleri | Engelm. ex A.Gray | Ranunculaceae | 8 |
| Thalictrum revolutum | DC. | Ranunculaceae | 8 |
| Thalictrum venulosum | Trel. | Ranunculaceae | 8 |
| Thelesperma filifolium | (Hook.) A.Gray | Asteraceae | 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 |
| Thelypodium texanum | (Cory) Rollins | Brassicaceae | 8 |
| Thelypodium wrightii | A.Gray | Brassicaceae | 8 |
| Thermopsis divaricarpa | A.Nelson | Fabaceae | 8 |
| Thermopsis montana | Nutt. | Fabaceae | 8 |
| Thermopsis rhombifolia | (Pursh) Richardson | Fabaceae | 8 |
| Thymophylla acerosa | (DC.) Strother | Asteraceae | 8 |
| Thymophylla pentachaeta | (DC.) Small | Asteraceae | 8 |
| Thymophylla setifolia | Lag. | Asteraceae | 8 |
| Thysanocarpus curvipes | Hook. | 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 gossypina | (Wooton & Standl.) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia greggii | (Torr. & A.Gray) A.T.Richardson | Ehretiaceae | 8 |
| Tiquilia hispidissima | (Torr. & A.Gray) A.T.Richardson | Ehretiaceae | 8 |
| Tomostima cuneifolia | (Nutt. ex Torr. & A.Gray) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Tomostima reptans | (Lam.) Al-Shehbaz, M.Koch & Jordon-Thaden | Brassicaceae | 8 |
| Tonestus pygmaeus | A.Nelson | Asteraceae | 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 grandiflora | Nutt. | Asteraceae | 8 |
| Townsendia incana | Nutt. | Asteraceae | 8 |
| Toxicodendron radicans | (L.) Kuntze | Anacardiaceae | 8 |
| Toxicoscordion paniculatum | (Nutt.) Rydb. | Melanthiaceae | 8 |
| Toxicoscordion venenosum | (S.Watson) Rydb. | Melanthiaceae | 8 |
| Trachypogon spicatus | (L.f.) Kuntze | Poaceae | 8 |
| Tradescantia occidentalis | (Britton) Smyth | Commelinaceae | 8 |
| Tradescantia pinetorum | Greene | Commelinaceae | 8 |
| Tradescantia wrightii | Rose & Bush | 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 |
| Trichogalium boreale | (L.) Fourr. | Rubiaceae | 8 |
| Trichogalium fendleri | (A.Gray) Kadereit & Schneew. | Rubiaceae | 8 |
| Trichostema arizonicum | A.Gray | Lamiaceae | 8 |
| Tridens albescens | (Vasey) Wooton & Standl. | Poaceae | 8 |
| Tridens flavus | (L.) Hitchc. | Poaceae | 8 |
| Tridens texanus | (S.Watson) Nash | Poaceae | 8 |
| Tridentopsis mutica | (Torr.) P.M.Peterson | Poaceae | 8 |
| Trifolium attenuatum | Greene | Fabaceae | 8 |
| Trifolium dasyphyllum | Torr. & A.Gray | Fabaceae | 8 |
| Trifolium gracilentum | Torr. & A.Gray | Fabaceae | 8 |
| Trifolium gymnocarpon | Nutt. | Fabaceae | 8 |
| Trifolium longipes | Nutt. | Fabaceae | 8 |
| Trifolium nanum | Torr. | Fabaceae | 8 |
| Trifolium parryi | A.Gray | Fabaceae | 8 |
| Trifolium pinetorum | Greene | Fabaceae | 8 |
| Trifolium wormskioldii | Lehm. | Fabaceae | 8 |
| Triglochin maritima | L. | Juncaginaceae | 8 |
| Triglochin palustris | L. | Juncaginaceae | 8 |
| Triodanis perfoliata | (L.) Nieuwl. | Campanulaceae | 8 |
| Triplasiella eragrostoides | (Vasey & Scribn.) P.M.Peterson & Romasch. | Poaceae | 8 |
| Triplasis purpurea | (Walter) Chapm. | Poaceae | 8 |
| Trixis californica | Kellogg | Asteraceae | 8 |
| Turritis glabra | L. | Brassicaceae | 8 |
| Typha angustifolia | L. | Typhaceae | 8 |
| Typha domingensis | Pers. | Typhaceae | 8 |
| Typha latifolia | L. | Typhaceae | 8 |
| Ungnadia speciosa | Endl. | Sapindaceae | 8 |
| Urochloa arizonica | (Scribn. & Merr.) Morrone & Zuloaga | Poaceae | 8 |
| Urochloa ciliatissima | (Buckley) 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 |
| Vaccinium cespitosum | Michx. | Ericaceae | 8 |
| Vaccinium myrtillus | L. | Ericaceae | 8 |
| Vaccinium scoparium | Leiberg ex Coville | Ericaceae | 8 |
| Vachellia constricta | (Benth.) Seigler & Ebinger | Fabaceae | 8 |
| Vachellia vernicosa | (Britton & Rose) Seigler & Ebinger | Fabaceae | 8 |
| Valeriana acutiloba | Rydb. | Caprifoliaceae | 8 |
| Valeriana arizonica | A.Gray | Caprifoliaceae | 8 |
| Valeriana edulis | Nutt. | Caprifoliaceae | 8 |
| Valeriana occidentalis | A.Heller | Caprifoliaceae | 8 |
| Valeriana sorbifolia | Kunth | Caprifoliaceae | 8 |
| Vallisneria americana | Michx. | Hydrocharitaceae | 8 |
| Veratrum californicum | Durand | Melanthiaceae | 8 |
| Verbena bipinnatifida | (Nutt.) Schauer | Verbenaceae | 8 |
| Verbena bracteata | Cav. ex Lag. & Rodr. | Verbenaceae | 8 |
| Verbena canadensis | (L.) Britton | Verbenaceae | 8 |
| Verbena canescens | Kunth | Verbenaceae | 8 |
| Verbena chiricahensis | (Umber) Moldenke | Verbenaceae | 8 |
| Verbena gooddingii | Briq. | Verbenaceae | 8 |
| Verbena halei | Small | 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 quadrangulata | A.Heller | Verbenaceae | 8 |
| Verbena racemosa | Eggert | Verbenaceae | 8 |
| Verbena scabra | Vahl | Verbenaceae | 8 |
| Verbena stricta | Vent. | Verbenaceae | 8 |
| Verbena tumidula | L.M.Perry | 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 besseya | M.M.Mart.Ort. & Albach | Plantaginaceae | 8 |
| Veronica catenata | Pennell | Plantaginaceae | 8 |
| Veronica peregrina | L. | Plantaginaceae | 8 |
| Veronica plantaginea | E.James | 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 macrorhizus | (Buckley) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vesper montanus | (Torr. & A.Gray) R.L.Hartm. & G.L.Nesom | Apiaceae | 8 |
| Vesper multinervatus | (J.M.Coult. & Rose) 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 missouriensis | Greene | Violaceae | 8 |
| Viola nephrophylla | Greene | Violaceae | 8 |
| Viola nuttallii | Pursh | Violaceae | 8 |
| Viola pedatifida | G.Don | Violaceae | 8 |
| Vitis acerifolia | Raf. | Vitaceae | 8 |
| Vitis arizonica | Engelm. | Vitaceae | 8 |
| Vitis riparia | Michx. | Vitaceae | 8 |
| Woodsia neomexicana | Windham | Woodsiaceae | 8 |
| Woodsia oregana | D.C.Eaton | Woodsiaceae | 8 |
| Woodsia phillipsii | Windham | Woodsiaceae | 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 |
| Xanthisma viscidum | (Wooton & Standl.) D.R.Morgan & R.L.Hartm. | Asteraceae | 8 |
| Xanthium orientale | L. | Asteraceae | 8 |
| Xanthium spinosum | L. | 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 campestris | McKelvey | Asparagaceae | 8 |
| Yucca elata | (Engelm.) Engelm. | Asparagaceae | 8 |
| Yucca faxoniana | (Trel.) Sarg. | Asparagaceae | 8 |
| Yucca glauca | Nutt. | Asparagaceae | 8 |
| Yucca harrimaniae | Trel. | Asparagaceae | 8 |
| Yucca madrensis | Gentry | Asparagaceae | 8 |
| Zannichellia palustris | L. | Potamogetonaceae | 8 |
| Zeltnera arizonica | (A.Gray) G.Mans. | Gentianaceae | 8 |
| Zeltnera exaltata | (Griseb.) G.Mans. | Gentianaceae | 8 |
| Zeltnera maryanniana | (B.L.Turner) G.Mans. | Gentianaceae | 8 |
| Zinnia acerosa | (DC.) A.Gray | Asteraceae | 8 |
| Zinnia grandiflora | Nutt. | Asteraceae | 8 |
| Zuloagaea bulbosa | (Kunth) Bess | Poaceae | 8 |
| Allium perdulce | S.V.Fraser | Amaryllidaceae | 7 |
| Amsonia fugatei | S.P.McLaughlin | Apocynaceae | 7 |
| Arcytophyllum fasciculatum | (A.Gray) Terrell & H.Rob. | Rubiaceae | 7 |
| Astragalus giganteus | S.Watson | Fabaceae | 7 |
| Astragalus pictiformis | Barneby | Fabaceae | 7 |
| Baccharis bigelovii | A.Gray | Asteraceae | 7 |
| Blepharidachne bigelovii | (S.Watson) Hack. | Poaceae | 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 |
| Carex simulata | Mack. | Cyperaceae | 7 |
| Corispermum americanum | (Nutt.) Nutt. | Chenopodiaceae | 7 |
| Crepis runcinata | (E.James) Torr. & A.Gray | Asteraceae | 7 |
| Cyperus pallidicolor | (Kük.) G.C.Tucker | Cyperaceae | 7 |
| Dalea filiformis | A.Gray | Fabaceae | 7 |
| Desmanthus obtusus | S.Watson | Fabaceae | 7 |
| Drymaria pachyphylla | Wooton & Standl. | Caryophyllaceae | 7 |
| Echinocereus dasyacanthus | Engelm. | Cactaceae | 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 |
| Helianthus paradoxus | Heiser | Asteraceae | 7 |
| Linanthus bigelovii | (A.Gray) Greene | Polemoniaceae | 7 |
| Mariosousa millefolia | (S.Watson) Seigler & Ebinger | Fabaceae | 7 |
| Melampodium longicorne | A.Gray | Asteraceae | 7 |
| Muhlenbergia villiflora | Hitchc. | Poaceae | 7 |
| Nicolletia edwardsii | A.Gray | Asteraceae | 7 |
| Paronychia wilkinsonii | S.Watson | Caryophyllaceae | 7 |
| Penstemon deaveri | Crosswh. | Plantaginaceae | 7 |
| Penstemon inflatus | Crosswh. | Plantaginaceae | 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 |
| Polypodium saximontanum | Windham | Polypodiaceae | 7 |
| Rumex orthoneurus | Rech.f. | Polygonaceae | 7 |
| Sageretia wrightii | S.Watson | Rhamnaceae | 7 |
| Salvia summa | A.Nelson | Lamiaceae | 7 |
| Scirpus pallidus | (Britton) Fernald | Cyperaceae | 7 |
| Scrophularia laevis | Wooton & Standl. | Scrophulariaceae | 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 gracilipes | Trel. | Asparagaceae | 6 |
| Amaranthus arenicola | I.M.Johnst. | Amaranthaceae | 6 |
| Astragalus wittmannii | Barneby | Fabaceae | 6 |
| Baccharis sulcata | DC. | Asteraceae | 6 |
| Bacopa rotundifolia | (Michx.) Wettst. | Plantaginaceae | 6 |
| Calystegia macounii | (Greene) Brummitt | Convolvulaceae | 6 |
| Carex oreocharis | Holm | Cyperaceae | 6 |
| Castilleja lineata | Greene | Orobanchaceae | 6 |
| Danthonia parryi | Scribn. | Poaceae | 6 |
| Delphinium sapellonis | Cockerell | Ranunculaceae | 6 |
| Descurainia adenophora | (Wooton & Standl.) O.E.Schulz | Brassicaceae | 6 |
| Echinocactus horizonthalonius | Lem. | Cactaceae | 6 |
| Erigeron melanocephalus | A.Nelson | Asteraceae | 6 |
| Euphrosyne acerosa | (Nutt.) Panero | Asteraceae | 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 |
| Heterotheca sierrablancensis | (Semple) G.L.Nesom | Asteraceae | 6 |
| Hymenoxys brachyactis | Wooton & Standl. | Asteraceae | 6 |
| Imperata brevifolia | Vasey | Poaceae | 6 |
| Indigofera sphaerocarpa | A.Gray | Fabaceae | 6 |
| Juncus triglumis | L. | Juncaceae | 6 |
| Lygodesmia grandiflora | (Nutt.) Torr. & A.Gray | Asteraceae | 6 |
| Marsilea mollis | B.L.Rob. & Fernald | Marsileaceae | 6 |
| Mentzelia reverchonii | (Urb. & Gilg) H.J.Thomps. & Zavort. | Loasaceae | 6 |
| Neoparrya lithophila | Mathias | Apiaceae | 6 |
| Oenothera organensis | Munz ex S.Emers. | Onagraceae | 6 |
| Oreocarya paysonii | J.F.Macbr. | Boraginaceae | 6 |
| Pelecyphora sneedii | (Britton & Rose) D.Aquino & Dan.Sánchez | Cactaceae | 6 |
| Phalaris angusta | Nees ex Trin. | Poaceae | 6 |
| Plantago argyrea | E.Morris | Plantaginaceae | 6 |
| Polygonum ramosissimum | Michx. | Polygonaceae | 6 |
| Rhinotropis rimulicola | (Steyerm.) J.R.Abbott | Polygalaceae | 6 |
| Senna orcuttii | (Britton & Rose) H.S.Irwin & Barneby | Fabaceae | 6 |
| Spermolepis organensis | G.L.Nesom | Apiaceae | 6 |
| Symphyotrichum porteri | (A.Gray) G.L.Nesom | Asteraceae | 6 |
| Townsendia fendleri | A.Gray | Asteraceae | 6 |
| Woodsia plummerae | Lemmon | Woodsiaceae | 6 |
| Abutilon hulseanum | (Torr. & A.Gray) Torr. ex Baker f. | Malvaceae | 5 |
| Apacheria chiricahuensis | C.T.Mason | Crossosomataceae | 5 |
| Aristida havardii | Vasey | Poaceae | 5 |
| Aristida schiedeana | Trin. & Rupr. | Poaceae | 5 |
| Astragalus cyaneus | A.Gray | Fabaceae | 5 |
| Astragalus oocalycis | M.E.Jones | Fabaceae | 5 |
| Astragalus proximus | (Rydb.) Wooton & Standl. | Fabaceae | 5 |
| Atriplex truncata | (Torr. ex S.Watson) A.Gray | Chenopodiaceae | 5 |
| Bothriochloa springfieldii | (Gould) Parodi | Poaceae | 5 |
| Carex jonesii | L.H.Bailey | Cyperaceae | 5 |
| Carex oederi | Retz. | Cyperaceae | 5 |
| Carex praeceptorum | Mack. | Cyperaceae | 5 |
| Carex ultra | L.H.Bailey | Cyperaceae | 5 |
| Chenopodium neomexicanum | Standl. | Chenopodiaceae | 5 |
| Crataegus wootoniana | Eggl. | Rosaceae | 5 |
| Cuscuta chinensis | Lam. | Convolvulaceae | 5 |
| Descurainia obtusa | (Greene) O.E.Schulz | Brassicaceae | 5 |
| Digitaria pubiflora | (Vasey) Wipff | Poaceae | 5 |
| Draba spectabilis | Greene | Brassicaceae | 5 |
| Echinocereus rigidissimus | (Engelm.) Rose | Cactaceae | 5 |
| Elymus arizonicus | (Scribn. & J.G.Sm.) Gould | Poaceae | 5 |
| Eriogonum atrorubens | Engelm. | Polygonaceae | 5 |
| Eriogonum gypsophilum | Wooton & Standl. | Polygonaceae | 5 |
| Euphorbia bilobata | Engelm. | Euphorbiaceae | 5 |
| Flaveria chlorifolia | A.Gray | Asteraceae | 5 |
| Gentiana fremontii | Torr. | Gentianaceae | 5 |
| Gutierrezia wrightii | A.Gray | Asteraceae | 5 |
| Mimosa rupertiana | B.L.Turner | Fabaceae | 5 |
| Mostacillastrum purpusii | (Brandegee) Al-Shehbaz | Brassicaceae | 5 |
| Muhlenbergia andina | (Nutt.) Hitchc. | Poaceae | 5 |
| Muhlenbergia dubia | E.Fourn. | Poaceae | 5 |
| Notholaena grayi | Davenp. | Pteridaceae | 5 |
| Oenothera neomexicana | (Small) Munz | Onagraceae | 5 |
| Packera quercetorum | (Greene) C.Jeffrey | Asteraceae | 5 |
| Penstemon griffinii | A.Nelson | Plantaginaceae | 5 |
| Plectocephalus rothrockii | (Greenm.) D.J.N.Hind | Asteraceae | 5 |
| Polygonum polygaloides | Meisn. | Polygonaceae | 5 |
| Pseudoclappia arenaria | Rydb. | Asteraceae | 5 |
| Psilactis brevilingulata | Sch.Bip. ex Hemsl. | Asteraceae | 5 |
| Rumex densiflorus | Osterh. | Polygonaceae | 5 |
| Schiedeella arizonica | P.M.Br. | Orchidaceae | 5 |
| Scrophularia macrantha | Greene ex Stiefelh. | Scrophulariaceae | 5 |
| Silene thurberi | S.Watson | Caryophyllaceae | 5 |
| Solidago pallida | (Porter) Rydb. | Asteraceae | 5 |
| Stenotis greenei | (A.Gray) Terrell & H.Rob. | Rubiaceae | 5 |
| Stevia micrantha | Lag. | Asteraceae | 5 |
| Allium bigelovii | S.Watson | Amaryllidaceae | 4 |
| Astragalus albulus | Wooton & Standl. | Fabaceae | 4 |
| Astragalus coltonii | M.E.Jones | Fabaceae | 4 |
| Astragalus ripleyi | Barneby | Fabaceae | 4 |
| Astragalus wingatanus | S.Watson | Fabaceae | 4 |
| Boechera consanguinea | (Greene) Windham & Al-Shehbaz | Brassicaceae | 4 |
| Boechera pseudoconsanguinea | Windham & Allphin | Brassicaceae | 4 |
| Bouteloua simplex | Lag. | Poaceae | 4 |
| Brickellia lemmonii | A.Gray | Asteraceae | 4 |
| Brickellia venosa | B.L.Rob. | Asteraceae | 4 |
| Chrysothamnus vaseyi | (A.Gray) Greene | Asteraceae | 4 |
| Chthamalia chihuahuensis | (A.Gray) Morillo | Apocynaceae | 4 |
| Cochlospermum palmatifidum | (DC.) Byng & Christenh. | Bixaceae | 4 |
| Cuscuta leptantha | Engelm. | Convolvulaceae | 4 |
| Cyperus dipsaceus | Liebm. | Cyperaceae | 4 |
| Cyperus hemidrummondii | Goetgh. | Cyperaceae | 4 |
| Cyperus setigerus | Torr. & Hook. | Cyperaceae | 4 |
| Delphinium ramosum | Rydb. | Ranunculaceae | 4 |
| Erigeron canus | A.Gray | Asteraceae | 4 |
| Erigeron eximius | Greene | Asteraceae | 4 |
| Erigeron grandiflorus | Hook. | Asteraceae | 4 |
| Eriogonum divaricatum | Hook. | Polygonaceae | 4 |
| Eriogonum scabrellum | Reveal | Polygonaceae | 4 |
| Euphorbia spurca | (M.C.Johnst.) A.M.Powell | Euphorbiaceae | 4 |
| Halenia rothrockii | A.Gray | Gentianaceae | 4 |
| Heteranthera rotundifolia | (Kunth) Griseb. | Pontederiaceae | 4 |
| Heuchera pulchella | Wooton & Standl. | Saxifragaceae | 4 |
| Ipomopsis pringlei | (A.Gray) Henrickson | Polemoniaceae | 4 |
| Lepidium ramosissimum | A.Nelson | Brassicaceae | 4 |
| Muhlenbergia ramulosa | (Kunth) Swallen | Poaceae | 4 |
| Muhlenbergia straminea | Hitchc. | Poaceae | 4 |
| Oenothera longissima | Rydb. | Onagraceae | 4 |
| Oreocarya bakeri | Greene | Boraginaceae | 4 |
| Packera hartiana | (A.Heller) W.A.Weber & Á.Löve | Asteraceae | 4 |
| Packera sanguisorboides | (Rydb.) W.A.Weber & Á.Löve | Asteraceae | 4 |
| Penstemon bleaklyi | O'Kane & K.D.Heil | Plantaginaceae | 4 |
| Penstemon lentus | Pennell | Plantaginaceae | 4 |
| Phlox caespitosa | Nutt. | Polemoniaceae | 4 |
| Podagrostis humilis | (Vasey) Björkman | Poaceae | 4 |
| Polemonium brandegeei | (A.Gray) Greene | Polemoniaceae | 4 |
| Potentilla subviscosa | Greene | Rosaceae | 4 |
| Sisyrinchium arizonicum | Rothr. | Iridaceae | 4 |
| Solidago mollis | Bartl. | Asteraceae | 4 |
| Stellaria calycantha | (Ledeb.) Bong. | Caryophyllaceae | 4 |
| Vernonia marginata | (Torr.) Raf. | Asteraceae | 4 |
| Agastache micrantha | (A.Gray) Wooton & Standl. | Lamiaceae | 3 |
| Agrostis variabilis | Rydb. | Poaceae | 3 |
| Amaranthus crassipes | Schltdl. | Amaranthaceae | 3 |
| Ammannia grayi | S.A.Graham & Gandhi | Lythraceae | 3 |
| Amsonia tharpii | Woodson | Apocynaceae | 3 |
| Artemisia franserioides | Greene | Asteraceae | 3 |
| Asclepias elata | Benth. | Apocynaceae | 3 |
| Asclepias macrotis | Torr. | Apocynaceae | 3 |
| Asclepias scaposa | Vail | Apocynaceae | 3 |
| Astragalus egglestonii | (Rydb.) Kearney & Peebles | Fabaceae | 3 |
| Astragalus humillimus | A.Gray | Fabaceae | 3 |
| Astragalus iodopetalus | (Rydb.) Greene ex Barneby | Fabaceae | 3 |
| Astragalus waterfallii | Barneby | Fabaceae | 3 |
| Boechera crandallii | (B.L.Rob.) W.A.Weber | Brassicaceae | 3 |
| Botrychium rubellum | Farrar & Stensvold | Ophioglossaceae | 3 |
| Botrychium tunux | Stensvold & Farrar | Ophioglossaceae | 3 |
| Carex nelsonii | Mack. | Cyperaceae | 3 |
| Carex scopulorum | Holm | Cyperaceae | 3 |
| Chenopodium cycloides | A.Nelson | Chenopodiaceae | 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 |
| Cuscuta legitima | Costea & Stefanović | Convolvulaceae | 3 |
| Cuscuta squamata | Engelm. | Convolvulaceae | 3 |
| Draba crassifolia | Graham | Brassicaceae | 3 |
| Echinocereus reichenbachii | (Terscheck ex Walp.) J.N.Haage | Cactaceae | 3 |
| Erigeron subtrinervis | Rydb. ex Porter & Britton | 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 |
| Gentianella amarella | (L.) Börner | Gentianaceae | 3 |
| Helianthus neglectus | Heiser | 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 springeri | (Standl.) Tidestr. | Loasaceae | 3 |
| Muhlenbergia pauciflora | Buckley | Poaceae | 3 |
| Muhlenbergia repens | (J.Presl) Hitchc. | Poaceae | 3 |
| Oreocarya paradoxa | A.Nelson | Boraginaceae | 3 |
| Orobanche multiflora | Nutt. | Orobanchaceae | 3 |
| Pectis longipes | A.Gray | Asteraceae | 3 |
| Penstemon alamosensis | Pennell & Nisbet | Plantaginaceae | 3 |
| Penstemon auriberbis | Pennell | Plantaginaceae | 3 |
| Penstemon cardinalis | Wooton & Standl. | Plantaginaceae | 3 |
| Phacelia bakeri | (Brand) J.F.Macbr. | Hydrophyllaceae | 3 |
| Phanerophlebia auriculata | Underw. | Dryopteridaceae | 3 |
| Phemeranthus parvulus | (Rose & Standl.) D.J.Ferguson & T.M.Price | Montiaceae | 3 |
| Physaria newberryi | A.Gray | Brassicaceae | 3 |
| Poa alpigena | Lindm. | Poaceae | 3 |
| Pseudoeriocoma eminens | (Cav.) Romasch. | Poaceae | 3 |
| Ranunculus cupulatus | (S.Watson) Christenh. & Byng | Ranunculaceae | 3 |
| Sambucus mexicana | C.Presl ex DC. | Viburnaceae | 3 |
| Senecio sacramentanus | Wooton & Standl. | Asteraceae | 3 |
| Silene wrightii | A.Gray | Caryophyllaceae | 3 |
| Suckleya suckleyana | (Torr.) Rydb. | Chenopodiaceae | 3 |
| Tamayorkis porphyrea | (Ridl.) Salazar & Soto Arenas | Orchidaceae | 3 |
| Thymophylla aurea | (A.Gray) Greene ex Britton & A.Br. | Asteraceae | 3 |
| Trichogalium microphyllum | (A.Gray) Kadereit & Schneew. | Rubiaceae | 3 |
| Valeriana texana | Steyerm. | Caprifoliaceae | 3 |
| Vauquelinia californica | (Torr.) Sarg. | Rosaceae | 3 |
| Woodsia cochisensis | Windham | Woodsiaceae | 3 |
Abies concolorwhite fir
Abies lasiocarpaAlpine Fir
Abronia angustifoliapurple sand verbena
Abronia bigeloviiGalisteo sand verbena
Abronia carneawinged sandpuffs
Abronia ellipticafragrant white sand verbena
Abronia fragranssnowball sand verbena
Abronia micranthasmallflower sandverbena
Abronia nealleyi
Abutilon fruticosumTexas Indian mallow
Abutilon incanumHoary Indian-mallow
Abutilon malacumyellow Indian mallow
Abutilon mollicomumSonoran Indian mallow
Abutilon parvulumdwarf Indian mallow
Abutilon wrightiiWright's Indian mallow
Acaciella angustissimaprairie acacia
Acalypha neomexicanaNew Mexico copperleaf
Acalypha persimilispineland threeseed mercury
Acalypha phleoidesshrubby copperleaf
Acer glabrumRocky Mountain maple
Acer negundobox elder
Acer rubrumred maple
Acer saccharumsugar maple
Achillea millefoliumcommon yarrow
Acleisanthes chenopodioidesgoosefoot moonpod
Acleisanthes diffusaspreading moonpod
Acleisanthes lanceolatagypsum moonpod
Acleisanthes longifloraangel's trumpets
Acmispon americanusSpanish clover
Acmispon brachycarpusfoothill deervetch
Acmispon neomexicanusGreene's bird's-foot trefoil
Acmispon oroboides
Acmispon wrightiiWright's deervetch
Aconitum columbianumColumbian Monkshood
Acourtia nanadwarf desertpeony
Acourtia wrightiibrownfoot
Actaea rubrared baneberry
Adenophyllum wrightiiWright's dogweed
Adiantum capillus-venerisblack maidenhair fern
Adolphia infestajunco
Adoxa moschatellinaMoschatel
Agalinis tenuifoliaslenderleaf false foxglove
Agastache pallidifloraBill Williams Mountain giant hyssop
Agave lechuguillalechuguilla
Agave palmeriPalmer's century plant
Agave parryiParry's agave
Agave schottiiSchott's century plant
Ageratina herbaceafragrant snakeroot
