| Latin Name | Common Name | Family | Synonyms | Edibility Rating | Medicinal Rating |
| Abies alba | Silver Fir, Christmas Tree Fir, European Silver Fir, Silver | Pinaceae | A. pectinata. A. picea. | 2 | 3 |
| Abies fraseri | She Balsam, Fraser fir, Southern Balsam Fir | Pinaceae | Pinus fraseri. | 1 | 3 |
| Abies lasiocarpa | Subalpine Fir, Alpine Fir | Pinaceae | A. subalpina. Pinus lasiocarpa. | 2 | 2 |
| Abies religiosa | Sacred Fir | Pinaceae | A. hirtella. Pinus religiosa. | 0 | 1 |
| Abies sachalinensis | Sakhalin Fir | Pinaceae | A. veitchii sachalinensis | 0 | 0 |
| Abies sibirica | Siberian Fir | Pinaceae | | 0 | 1 |
| Abronia fragrans | Snowball Sand Verbena | Nyctaginaceae | A. speciosa. | 2 | 1 |
| Abronia latifolia | Sand Verbena, Coastal sand verbena | Nyctaginaceae | A. arenaria. | 2 | 0 |
| Abutilon vitifolium | | Malvaceae | Sida vitifolia. Cav. Corynabutilon vitifolium. | 3 | 0 |
| Acacia concinna | Shikakai, Soap-Pod | Fabaceae | Acacia hooperiana Zipp. ex Miq. Acacia philippinarurn Benth. Acacia poilanei Gagnep. Acacia polyceph | 2 | 1 |
| Acacia farnesiana | Sweet Acacia, Perfume Acacia, Huisache | Fabaceae or Leguminosae | | 2 | 2 |
| Acacia holosericea | Strap wattle, Candelabra wattle | Fabaceae | Acacia mangium holosericea (A.Cunn. ex G.Don) C.T.WhiteRacosperma holosericeum (A.Cunn. ex G.Don) Pedley | 1 | 2 |
| Acacia longifolia | Sydney Golden Wattle, Acacia | Fabaceae or Leguminosae | Mimosa longifolia. | 3 | 0 |
| Acacia retinodes | Swamp Wattle, Water wattle | Fabaceae or Leguminosae | | 2 | 0 |
| Acer pseudoplatanus | Sycamore, Great Maple, Scottish Maple, Planetree Maple | Aceraceae | | 2 | 1 |
| Acer saccharinum | Silver Maple, River Maple, Soft Maple | Aceraceae | A. dasycarpum. A. eriocarpum. | 3 | 1 |
| Acer saccharum | Sugar Maple, Florida Maple, Hard Maple, Rock Maple | Aceraceae | A. saccharinum. (Non L.) | 4 | 2 |
| Acer truncatum | Shantung Maple, Purpleblow Maple | Aceraceae | | 1 | 0 |
| Achillea ptarmica | Sneeze-Wort, Sneezeweed | Asteraceae or Compositae | | 2 | 1 |
| Achillea sibirica | Siberian Yarrow | Asteraceae or Compositae | A. alpina. L. A. mongolica. Fisch. | 1 | 1 |
| Aciphylla squarrosa | Speargrass | Apiaceae or Umbelliferae | | 2 | 0 |
| Acorus calamus | Sweet Flag - Calamus | Araceae | Calamus aromaticus | 3 | 4 |
| Acourtia microcephala | Sacapellote | Asteraceae or Compositae | Perezia microcephala. | 0 | 1 |
| Actinidia polygama | Silver Vine | Actinidiaceae | A. volubilis. (Sieb.&Zucc.)Planch. Trochostigma polygama. Sieb.&Zucc. | 4 | 2 |
| Adenophora stricta | Sha Shen, Ladybells | Campanulaceae | | 2 | 1 |
| Aesculus flava | Sweet Buckeye, Yellow buckeye | Hippocastanaceae | Ae lutea. Ae octandra. | 4 | 0 |
| Agalinis tenuifolia | Slenderleaf False Foxglove | Scrophulariaceae | Gerardia tenuifolia. | 0 | 1 |
| Agave sisalana | Sisal | Asparagaceae | Agave amaniensis Trel. & Nowell Agave rigida sisalana (Perrine) Engelm. Agave segurae D.Guillot & P. | 2 | 2 |
| Agriophyllum squarrosum | Sand Rice | Chenopodiaceae | | 1 | 0 |
| Albizia lebbeck | Siris Tree, Woman's Tongue, East Indian Walnut | Fabaceae | Acacia lebbeck (L.) Willd. Acacia macrophylla Bunge Acacia speciosa (Jacq.) Willd. Albizia latifolia | 1 | 2 |
| Albuca amboensis | Slime Lily | Hyacinthaceae | | 2 | 0 |
| Albuca canadensis | Slime Lily, Albuca | Hyacinthaceae | | 1 | 0 |
| Albuca major | Slime Lily | Hyacinthaceae | | 1 | 0 |
| Allium brevistylum | Shortstyle Onion | Alliaceae | | 3 | 2 |
| Allium cepa ascalonicum | Shallot | Alliaceae | A. ascalonicum. | 5 | 3 |
| Allium flavum | Small Yellow Onion, Ornamental Onion | Alliaceae | | 2 | 2 |
| Allium sativum ophioscorodon | Serpent Garlic | Alliaceae | | 5 | 5 |
| Allium validum | Swamp Onion, Pacific onion | Alliaceae | | 3 | 2 |
| Alnus maritima | Seaside Alder, Beach Alder | Betulaceae | | 0 | 0 |
| Alnus rugosa | Speckled Alder | Betulaceae | A. incana rugosa. (Duroi.)Clausen. | 0 | 2 |
| Alnus serrulata | Smooth Alder, Hazel alder | Betulaceae | Betula serrulata. | 0 | 2 |
| Alnus sinuata | Sitka Alder | Betulaceae | A. viridis sinuata. (Reg.)Love.&Love. | 1 | 1 |
| Alopecurus aequalis | Shortawn Foxtail, Sonoma shortawn foxtail | Poaceae or Gramineae | A. fulvus. | 1 | 1 |
| Amaranthus blitum | Slender Amaranth, Purple amaranth | Amaranthaceae | A. blitum. L. | 4 | 1 |
| Amaranthus dubius | Spleen Amaranth | Amaranthaceae | | 2 | 0 |
| Amaranthus graecizans | Spreading Pigweed, Mediterranean amaranth | Amaranthaceae | | 2 | 0 |
| Amaranthus spinosus | Spiny Amaranth | Amaranthaceae | | 2 | 3 |
| Amelanchier alnifolia | Saskatoon, Saskatoon serviceberry, Serviceberry | Rosaceae | Aronia alnifolia. | 5 | 2 |
| Amelanchier obovalis | Southern Juneberry, Coastal serviceberry | Rosaceae | Mespilus canadensis obovalis. | 3 | 0 |
| Amelanchier ovalis | Snowy Mespilus, Dwarf Garden Serviceberry | Rosaceae | A. rotundifolia. (Lam.)Dum-Cours. A. vulgaris. Crataegus rotundifolia. Mespilus amelanchier. | 2 | 0 |
| Anagallis arvensis | Scarlet Pimpernel | Primulaceae | | 2 | 2 |
| Angophora cordifolia | Smooth-Barked Apple | Myrtaceae | A. costata. Domin. A. lanceolata. | 0 | 1 |
| Annona muricata | Sour Sop | Annonaceae | Annona bonplandiana Kunth Annona cearaensis Barb.Rodr. Annona macrocarpa Werckl? Guanabanus muricatu | 4 | 3 |
| Annona squamosa | Sugar Apple, Sweetsop, Custard Apple | Annonaceae | Annona asiatica L. Annona biflora Mo?. & Sess? Annona cinerea Dunal Annona forskahlii DC. Guanabanus | 5 | 2 |
| Anthoxanthum odoratum | Sweet Vernal Grass | Poaceae or Gramineae | | 2 | 2 |
| Antirrhinum majus | Snapdragon, Garden snapdragon | Scrophulariaceae | | 1 | 1 |
| Apium prostratum | Sea Celery, Prostrate marshwort | Apiaceae or Umbelliferae | | 3 | 0 |
| Apocynum androsaemifolium | Spreading Dogbane | Apocynaceae | | 0 | 2 |
| Aquilegia brevistyla | Smallflower columbine | Ranunculaceae | | 2 | 1 |
| Aralia schmidtii | Sakhalin Spikenard | Araliaceae | | 2 | 0 |
| Arbutus unedo | Strawberry Tree | Ericaceae | | 4 | 2 |
| Arctostaphylos stanfordiana | Stanford's manzanita, Rincon manzanita | Ericaceae | | 3 | 0 |
| Arenga pinnata | Solitary Sugar Palm | Arecaceae | Arenga gamuto Merr. Arenga griffithii Seem. ex H.Wendl. Arenga saccharifera Labill. ex DC. Borassus | 4 | 1 |
| Aristolochia rotunda | Snakeroot | Aristolochiaceae | | 0 | 2 |
| Armeria maritima | Sea Thrift, Thrift seapink, California seapink, Interior seapink, Siberian sea thrift | Plumbaginaceae | A. elongata. A. vulgaris. Statice armeria. S. maritima. | 1 | 1 |
| Artemisia abrotanum | Southernwood | Asteraceae or Compositae | Artemisia altissima Ehrh. ex DC. International Compositae Alliance ILDIS IOPI New Yo | 1 | 3 |
| Artemisia filifolia | Sand Sage, Sand sagebrush | Asteraceae or Compositae | | 0 | 2 |
| Artemisia laciniata | Siberian wormwood | Asteraceae or Compositae | | 1 | 0 |
| Artemisia maritima | Sea Wormwood | Asteraceae or Compositae | Seriphidium maritimum. (L.)Soják. | 1 | 2 |
| Artemisia schmidtiana | Sagebrush, Silvermound, Wormwood, Mugwort | Asteraceae or Compositae | | 1 | 0 |
| Artemisia tridentata | Sage Brush, Big sagebrush, Bonneville big sagebrush | Asteraceae or Compositae | Seriphidium tridentatum. (Nutt.)W.A.Weber. | 3 | 2 |
| Arthrocnemum fruticosum | Glasswort | Chenopodiaceae | Salicornia fruticosa. L. | 1 | 0 |
| Arthropodium minus | Small Vanilla Lily | Asphodelaceae | | 2 | 0 |
| Artocarpus mariannensis | Seeded breadfruit, Marianas bread | Moraceae | Saccus mariannensis Kuntze Unresolved | 4 | 3 |
| Asarum canadense | Snake Root, Canadian wildginger, Canada Wild Ginger, Wild Ginger | Aristolochiaceae | | 3 | 3 |
| Asclepias incarnata | Swamp Milkweed, Swamp Butterfly Weed, Marsh Milkweed | Asclepiadaceae | | 3 | 2 |
| Asclepias speciosa | Showy Milkweed | Asclepiadaceae | | 3 | 2 |
| Asparagus racemosus | Shatavari | Asparagaceae | | 3 | 5 |
| Asperula cynanchica | Squinancy Wort | Rubiaceae | | 0 | 1 |
| Asplenium ceterach | Scale Fern | Polypodiaceae | Ceterach officinarum. DC. | 0 | 2 |
| Aster tripolium | Sea Aster | Asteraceae or Compositae | | 2 | 1 |
| Astragalus boeticus | Swedish Coffee | Fabaceae or Leguminosae | | 2 | 0 |
| Astragalus diphysus | Specklepod Milkvetch, Freckled milkvetch | Fabaceae or Leguminosae | A. lentignosus diphysus. (Gray.)M.E.Jones. | 3 | 0 |
| Atriplex argentea | Silvery Orach, Silverscale saltbush, Stalked saltbush | Chenopodiaceae | | 2 | 2 |
| Atriplex argentea expansa | Silverscale Saltbush | Chenopodiaceae | A. expansa. S. Wats. | 2 | 0 |
| Atriplex confertifolia | Shadscale, Shadscale saltbush | Chenopodiaceae | A. jonesii. Obione confertifolia. | 4 | 1 |
| Atriplex glabriuscula | Scotland orache, Maritime saltbush, Frankton's saltbush, Northeastern saltbush | Chenopodiaceae | | 2 | 0 |
| Atriplex halimus | Sea Orach, Saltbush | Chenopodiaceae | | 5 | 1 |
| Atriplex patula | Spreading Orach, Spear saltbush | Chenopodiaceae | | 3 | 1 |
| Atriplex saccaria | Sack Saltbush | Chenopodiaceae | | 2 | 0 |
| Aucuba japonica | Spotted Laurel, Japanese laurel, Japanese Gold Dust Tree | Aucubaceae | | 1 | 1 |
| Avena barbata | Slender Oat | Poaceae or Gramineae | | 2 | 0 |
| Avena sterilis | Sterile Oats, Animated oat | Poaceae or Gramineae | | 3 | 0 |
| Bambusa blumeana | Spiny Bamboo. Spiny bamboo, Thorny bamboo | Poaceae | Bambusa pungens Blanco Bambusa spinosa Blume ex Nees | 2 | 0 |
| Banksia marginata | Silver Banksia | Proteaceae | | 2 | 0 |
| Bassia scoparia | Summer Cypress, Burningbush | Chenopodiaceae | Chenopodium scoparia. Kochia scoparia. (L.)Schrad. K. trichophila. | 2 | 2 |
| Beckmannia eruciformis | Sloughgrass | Poaceae or Gramineae | B. syzigachne. (Steud.)Fern. | 2 | 0 |
| Berberis aggregata | Salmon Barberry | Berberidaceae | B. geraldi | 3 | 2 |
| Bergenia cordifolia | Siberian-tea, Pigsqueak, Heartleaf Bergenia | Saxifragaceae | | 0 | 0 |
| Bergenia crassifolia | Siberian Tea | Saxifragaceae | B. bifolia. Saxifraga crassifolia. | 2 | 0 |
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