| Amaranthus spinosus |
Spiny Amaranth |
| Amaranthus tuberculatus |
Tubercled Amaranth |
| Ambrosa artemisiifolia |
Common Ragweed |
| Ambrosia acanthicarpa |
Flatspine Burr Ragweed |
| Ambrosia artemisiifolia |
Annual Ragweed |
| Ambrosia bidentata |
Lanceleaf Ragweed |
| Ambrosia coronopifolia |
Ragweed |
Ambrosia psilostachya  |
Western Ragweed |
Ambrosia trifida  |
Giant Ragweed |
| Amelanchier alnifolia |
Saskatoon Serviceberry |
| Amelanchier arborea |
Juneberry |
| Amelanchier bartramiana |
Oblongfruit Serviceberry |
| Amelanchier canadensis |
|
| Amelanchier humilis |
Huron Juneberry |
| Amelanchier interior |
Pacific Serviceberry |
| Amelanchier laevis |
Smooth Juneberry |
| Amelanchier lamarckii |
Apple Serviceberry |
| Amelanchier ovalis |
Snowy Mespilus |
| Amelanchier sanguinea |
Roundleaf Serviceberry |
| Amelanchier stolonifera |
Running Serviceberry |
| Amelanchier utahensis |
Great Basin Serviceberry |
| Amerorchis rotundifolia |
Small Round-Leaved Orchis |
| Ammannia coccinea |
Scarlet Ammannia |
| Ammannia robusta |
Grand Redstem |
| Ammi majus |
Bishop's Flower |
| Ammophila breviligulata |
American Beachgrass |
| Amorpha canescens |
Lead Plant |
| Amorpha fructicosa |
|
| Amorpha fruticosa |
False Indigo |
| Amorpha nana |
Fragrant False Indigo |
| Amphicarpaea bracteata |
Hog Peanut |
| Amsonia illustris |
Blue Star |
| Amsonia tabernaemontana |
|
| Anagallis arvensis |
Scarlet Pimpernel |
| Anagallis arvensis ssp arvensis |
Scarlet Pimpernel |
| Anagallis minima |
Chaffweed |
| Anaphalis margaritacea |
Pearly Everlasting |
| Anchusa arvensis |
Small Bugloss |
| Andromeda glaucophylla |
Bog Rosemary |
| Andromeda polifolia |
Bog Rosemary |
| Andropogon gerardii |
Big Bluestem |
| Andropogon hallii |
Sand Bluestem |
| Andropogon scoparius |
|
| Androsace occidentalis |
Western Rockjasmine |
| Androsace septentrionalis |
Pygmyflower Rockjasmine |
| Androsace septentrionalis ssp puberulenta |
Pygmyflower Rockjasmine |
| Anemone acutiloba |
Sharp-Lobed Hepatica |
| Anemone americana |
Round-Lobed Hepatica |
| Anemone canadensis |
Canada Mayflower |
| Anemone caroliniana |
Thimbleweed |
| Anemone cylindrica |
Thimbleweed |
| Anemone multifida |
Pacific Anemone |
| Anemone patens |
Pasque Flower |
| Anemone patens wolfgangiana |
Pasque Flower |
| Anemone quinquefolia |
Wood Anemone |
| Anemone virginiana |
Tall Thimbleweed |
| Anethum graveolens var 'Bouquet' |
Dill |
| Anethum graveolens var 'Dukat' |
Dill |
| Anethum graveolens var 'Fern Leaf' |
Dill |
| Anethum graveolens var 'Mammoth' |
Dill |
| Angelica atropurpurea |
Angelica |
| Angelica venenosa |
Hairy Angelica |
| Annona squamosa |
Custard Apple |
| Antennaria howellii |
Howell's Pussytoes |
| Antennaria howellii ssp canadensis |
Canadian Pussytoes |
| Antennaria howellii ssp neodioica |
Howell's Pussytoes |
| Antennaria howellii ssp petaloidea |
Small Pussytoes |
| Antennaria microphylla |
Littleleaf Pussytoes |
| Antennaria neglecta |
Pussy Toes |
| Antennaria parlinii |
Parlin's Pussytoes |
| Antennaria parlinii ssp fallax |
Parlin's Pussytoes |
| Antennaria parlinii ssp parlinii |
Parlin's Pussytoes |
| Antennaria parvifolia |
Small Leaf Pussytoes |
| Antennaria plantaginifolia |
Plantain-Leaved Pussytoes |
| Antennaria rosea |
Rosy Pussytoes |
| Antennaria rosea ssp rosea |
Rosy Pussytoes |
| Anthemis cotula |
Stinking Chamomile |
| Anthemis nobilis |
|
| Anthemis tinctoria |
Golden Chamomile |
| Anthoxanthum aristatum |
Annual Vernalgrass |
| Anthriscus cerefolium |
Chervil |
| Anthriscus sylvestris |
Wild Chervil |
| Antirrhinum braun-blanquetii |
Perennial Snapdragon |
| Antirrhinum majus |
Snapdragon |
| Apios americana |
Groundnut |
| Aplectrum hyemale |
Puttyroot |
| Apocynum androsaemifolium |
Spreading Dogbane |
| Apocynum cannabinum |
Indian Hemp |
| Apocynum sibiricum |
Clasping Dogbane |
| Aquilegia brevistyla |
Smallflower Columbine |
| Aquilegia caerulea |
|
| Aquilegia caerulea var '(mixed)' |
|
| Aquilegia canadensis |
Wild Columbine |
| Aquilegia formosa |
|
| Aquilegia oxysepala |
|
| Aquilegia vulgaris |
Dwarf Columbine |
| Arabidopsis thaliana |
Mouseear Cress |
| Arabis alpina |
|
| Arabis canadensis |
Sicklepod |
| Arabis divaricarpa |
Spreadingpod Rockcress |
| Arabis drummondii |
Drummond's Rockcress |
| Arabis glabra |
Tower Rockcress |
| Arabis hirsuta |
Hairy Rockcress |
| Arabis holboellii |
Holboell's Rockcress |
| Arabis laevigata |
Smooth Rock Cress |
| Arabis lyrata |
Lyrate Rockcress |
| Arabis shortii |
Stellate Rock Cress |
| Aralia elata |
Angelica Tree |
| Aralia hispida |
Bristly Sarsasparilla |
| Aralia nudicaulis |
Wild Sarsaparilla |
| Aralia racemosa |
American Spikenard |
| Aralia racemosa ssp racemosa |
American Spikenard |
| Aralia spinosa |
American Aralia Tree |
| Aralia stipulata |
Chinese Angelica Tree |
| Araucaria araucana |
Monkey Puzzle Tree |
| Arbutus menziesii |
Madrone |
| Arceuthobium pusillum |
Eastern Dwarf Mistletoe |
| Arctium minus |
Common Burdock |
| Arctium tomentosum |
Woolly Burrdock |
| Arctostaphylos nevadensis |
Pine-Mat Manzanita |
| Arctostaphylos patula |
Greenleaf Manzanita |
| Arctostaphylos uva-ursi |
Kinnikinnick |
| Arctostaphylos viscida |
Whiteleaf Manzanita |
| Arctotis stoechadifolia |
African Daisy |
| Ardisia japonica |
Marlberry |
| Arenaria dawsonensis |
Rock Sandwort |
| Arenaria serpyllifolia |
Thymeleaf Sandwort |
| Arethusa bulbosa |
Dragon's Mouth |
| Argemone polyanthemos |
Prickly Poppy |
| Argentina anserina |
Silverweed Cinquefoil |
| Arisaema dracontium |
Green Dragon |
| Arisaema triphyllum |
Jack-In-The-Pulpit |
| Arisaema triphyllum ssp pusillum |
Jack In The pulpit |
| Arisaema triphyllum ssp stewardsonii |
Jack In The pulpit |
| Arisaema triphyllum ssp triphyllum |
Jack In The pulpit |
| Aristida basiramea |
Base-Branched Three-Awn |
| Aristida dichotoma |
Churchmouse Threeawn |
| Aristida longispica |
Slimspike Threeawn |
| Aristida oligantha |
Prairie Threeawn |
| Aristida purpurea |
Red Three-Awn |
| Aristida tuberculosa |
Sea-Beach Needle Grass |
| Aristolochia tomentosa |
Dutchman's Pipe |
| Armoracia rusticana |
Horseradish |
| Arnica lonchophylla |
Longleaf Arnica |
| Arnica lonchophylla ssp lonchophylla |
Longleaf Arnica |
| Arnoglossum atriplicifolium |
Pale Indian Plaintain |
| Arnoglossum muehlenbergii |
Great Indian Plaintain |
| Arnoglossum plantagineum |
Tuberous Indian Plantain |
| Aronia melanocarpa |
Black Chokeberry |
| Arrhenatherum elatius |
Tall Oatgrass |
| Artemisia abrotanum |
Southernwood |
| Artemisia absinthium |
Absinthium |
| Artemisia biennis |
Biennial Wormwood |
| Artemisia campestris |
Tall Wormwood |
| Artemisia campestris ssp borealis |
Field Sagewort |
| Artemisia campestris ssp caudata |
Field Sagewort |
| Artemisia cana |
Silver Sagebrush |
| Artemisia cana ssp cana |
Silver Sagebrush |
| Artemisia caudata |
Beach Wormwood |
| Artemisia dracunculus |
Tarragon |
| Artemisia frigida |
Prairie Sagewort |
| Artemisia ludoviciana |
Prairie Sage |
| Artemisia ludoviciana ssp ludoviciana |
White Sagebrush |
| Artemisia nova |
Black Sagebrush |
| Artemisia pontica |
Roman Wormwood |
| Artemisia serrata |
Leafy Mugwort |
| Artemisia stelleriana |
Oldwoman |
| Artemisia tridentata v tridentata |
Basin Big Sagebrush |
| Artemisia tridentata v vaseyana |
Mountain Big Sagebrush |
| Artemisia tridentata var 'Nova' |
Black Sagebrush |
| Artemisia tridentata var 'Vaseyana' |
Mtn. Big Sagebrush |
| Artemisia tridentata var 'Wyomingensis' |
WY Big Sagebrush |
| Artemisia vulgaris |
Common Wormwood |
| Aruncus dioicus |
Goat's Beard |
| Asarum canadense |
Wild Ginger |
| Asclepias amplexicaulis |
Blunt-leaved Milkweed |
| Asclepias curassavica |
|
| Asclepias exaltata |
Poke Milkweed |
| Asclepias hallii |
Hall's Milkweed |
| Asclepias hirtella |
Tall Green Milkweed |
| Asclepias incarnata |
Swamp Milkweed |
| Asclepias incarnata ssp incarnata |
Swamp Milkweed |
| Asclepias lanuginosa |
Sidecluster Milkweed |
| Asclepias ovalifolia |
Oval-Leaved Milkweed |
| Asclepias purpurascens |
Purple Milkweed |
| Asclepias quadrifolia |
Fourleaf Milkweed |
| Asclepias rubra |
|
| Asclepias speciosa |
Showy Milkweed |
| Asclepias stenophylla |
Narrow Leaved Milkweed |
| Asclepias sullivantii |
Prairie Milkweed |
| Asclepias syriaca |
Common Milkweed |
| Asclepias tuberosa |
Butterfly Milkweed |
| Asclepias tuberosa ssp interior |
Butterfly Milkweed |
| Asclepias verticillata |
Whorled Milkweed |
| Asclepias viridiflora |
Short Green Milkweed |
| Asclepias viridis |
|
| Asimina triloba |
Pawpaw |
| Asparagus officinalis |
Wild Asparagus |
| Asperugo procumbens |
German Madwort |
| Asplenium platyneuron |
Ebony Spleenwort |
| Asplenium rhizophyllum |
Walking Fern |
