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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