Apocynum androsaemifolium (spreading dogbane) -- cor 6-10mm, pnksh, w/ sprding or recrvd lobes; lvs def petiolate, drooping
Apocynum cannabinum (Indian hemp dogbane) -- cor 3-6mm greenish-white or white; lvs erect; acute to rounded at base
Apocynum sibiricum -- cor 3-6mm greenish-white or pale yellow; lvs sessile or short petioles, lvs at base obtuse, rnd, or cordate
Apocynum sp. (dogbane) Apocynaceae ((5) (5) 5 1 hypo) 369 --
Aquifoliaceae (holly) -- Ilex, Nemopanthus (mtn holly)
Aquilegia canadensis (columbine) Ranunculaceae (5z 5 N ?) 059 --
Arabidopsis thaliana (mouse-ear cress) Brassicaceae (4 4 4+2 1) 181
Arabis canadensis (sickle pod mustard) 175 -- creamy-white fls; sparsely hairy at base; lvs +or- hairy
Arabis drummondii 175
Arabis glabra (tower mustard) 174 -- stem glaucous;lvs AE & clasping
Arabis hirsuta (hairy rockcress) 174 -- stem & lower lvs hairy; entire lvs, small rosette at base
Arabis laevigata (smooth rockcress) 175 -- stem glaucous; cauline lvs glabrous, AE clasping; fr pods very curved, drooping
Arabis lyrata (lyre-leaved rockcress) 174 -- deeply lobed lvs in small rosette at base
Arabis shortii 176
Arabis sp. Brassicaceae (4 4 4+2 1)
Araceae (arum) -- Arisaema, Calla, Peltandra, Pinellia, Orontium, Symplocarpus
Aralia hispida (bristly sarsaparilla) 342 -- to 1.5m; sharply bristly lnear the base; lflts sharply serrate; dry woods, esp in sandy or sterile soil
Aralia nudicaulis (wild sarsaparilla) 342 -- gr-white, us in 3 umbels on top of naked stalk; BDT 3 groups of 5 lflts
Aralia racemosa (spikenard) 343 -- herb to 2m; lvs few, widely spreading, to 8 dm, pinnately compound, lflts ovate, often doubly serrate; hairs reddish brown; moist or wet woods
Aralia sp. (sarsaparilla) Araliaceae (5 5 5 1 epi) --
Aralia spinosa (hercules' club) 342 -- shrub or tree w/ stout prickles; lvs to 1 m, twice or partly thrice compound, serrate; fr black; rich woods
Araliaceae (ginseng) -- Aralia (sarsaparilla), Hedera (English ivy), Panax (ginseng)
Arctium lappa (burdock) Asteraceae/Cynareae 579 -- longer petiole; lf stalk solid; fls to 1.5" wide
Arcticum minus (common burdock) Asteraceae/Cynareae 579 -- short petiole; lf stalk hollow; fls to 1" wide
Arctium tomentosum (cotton burdock) Asteraceae/Cynareae 579 --
Arctostaphylos uva-ursi (bearberry) Ericaceae ((5) 5 10 1) 190 --
Arenaria caroliniana (pine barren sandwort) --
Arenaria lateriflora (blunt-leaved sandwort)--
Arenaria serpyllifolia (thyme-leaved sandwort)--
Arenaria sp. (sandwort) Caryophyllaceae (5 5 10 3) 100-101 --
Arenaria stricta (rock sandwort) -- white in widely branching clusters; WE linear in dense clusters Arethusa bulbosa (arethusa) Orchidaceae (2+1z 3 1-2 3) 824 -- magenta-pink 1-2" fls, lower lip purple-spotted crested w yellow hairs; NONE
Arisaema dracontium (dragon arum) Araceae (spathe & spadix) 616 -- infl solitary w/ long-tail-like spadix; BD 5-15 lflts
Arisaema triphyllum (jack-in-pulpit) Araceae (spathe & spadix) 616 --
Aristida adscensionis (three-awn grass) Poaceae 734 --
Aristida dichotoma (church mouse three-awn grass) Poaceae 733 -- paramecium w awn between 2 scales (v-shaped); curled basal lvs
Aristida lanosa (woolly three-awn grass) Poaceae 735 --
Aristida longespica var. longespica (slender three-awn grass) Poacea 735 --
Aristida oligantha (prairie three-awn grass) Poaceae 733 -- 3 long bristles on each fl, slightly twisted at the base; sterile soil
Aristida purpurascens (arrowfeather three-awn grass) Poaceae 733 --
Aristida tuberculosa (three-awn grass) Poaceae 734 --
Aristida virgata Poaceae 733 --
Aristolochia clematitis (birthwort) Aristolochiaceae (0 (3) 6 (6)) 041 --
Aristolochia macrophylla (Dutchman's pipe) Aristolochiaceae (0 (3) 6 (6)) 041 --
Aristolochia serpentaria (Virginia snakeroot) Aristolochiaceae (0 (3) 6 (6)) 041 --lvs w/ heart-shaped base
Aristolochiaceae (birthwort) -- Aristolochia (birthwort); Asarum (ginger)
Armoracia lacustris (lake cress) Brassicaceae (4 4 4+2 1) 170
Armoracia rusticana (horse radish) Brassicaceae (4 4 4+2 1) 170 -- large, long stalked basal lvs; escaped to roadsides & along streams
Arnoseris minima (dwarf nipplewort) Asteraceae/Lactuceae 600 --
Aronia arbutifolia (red chokeberry) Rosaceae (5 5 N 5) 245 -- lf densy hairy below
Aronia melanocarpa (black chokeberry) Rosaceae (5 5 N 5) 245 -- lf glabrous or nearly so; of the 3 species, most toothed
Aronia x prunifolia (purple chokeberry) Rosaceae (5 5 N 5) 245 -- lf more rotund; often glabrate; hardly looks toothed at all
Arrhenatherum elatius (tall oat grass) Poaceae 709 --
Artemisia abrotanum (southern wood mugwort) 520 -- lvs very thin, green above, 2-3 times pinnatifid; roadsides & waste pls.
Artemisia absinthium (common wormwort) 522 -- lvs white below; receptacle beset w/ numerous long hairs between disk-fls; fields & waste pls.
Artemisia annua (annual wormwort) 521 -- lvs green below, 2-3 times pinnatifid; infl loose; fields & waste pls.
Artemisia biennis (biennial wormwort) 521 -- lvs green below; infl dense; waste pls & stream banks, esp in sandy soil
Artemisia campestris (field wormwort) -- open pls., often in sandy soil
Artemisia ludoviciana (white sage mugwort) 521 -- lvs white below, entire in var ludoviciana; prairies, dry ground & waste pls.
Artemisia pontica (Black Sea wormwort) 520 -- lvs white tomentose, both sides, 2-3 times pinnatifid; dry open pls.
Artemisia serrata (mugwort) 520 -- lvs white below; prairies & low ground; introduced from midwest
Artemisia sp. (mugwort) Asteraceae/Anthemideae 520-521 --
Artemisia stelleriana (beach wormwort or dusty miller) 520 -- lvs whitened; sandy beaches
Artemisia vulgaris (common mugwort) 520 -- lvs white below; fields, roadsides, waste pls. Arthraxon hispidus Poaceae 773 --
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