sage, silver king artemisia, white wormwood, white sagebrush X Artemisia pontica – Roman wormwood, petite wormwood, green ginger X Artemisia stelleriana – hoary sagebrush, dusty miller, beach wormwood, old woman N Artemisia tilesii – Tilesius' wormwood, mountain sagewort, oldwoman X Artemisia vulgaris – common mugwort, common wormwood Aruncus X Aruncus dioicus – common goat's-beard As Asarum N Asarum canadense – Canada wild ginger Asclepias N Asclepias exaltata – poke milkweed, tall milkweed, four-leaved milkweed N Asclepias hirtella – tall green milkweed N Asclepias incarnata – swamp milkweed N Asclepias ovalifolia – oval-leaf milkweed, dwarf milkweed N Asclepias purpurascens – purple milkweed N Asclepias quadrifolia – four-leaved milkweed N Asclepias sullivantii – Sullivant's milkweed N Asclepias syriaca – common milkweed, silkweed, silky swallow-wort N Asclepias tuberosa – butterfly weed, orange milkweed, pleurisy root, chigger flower ? Asclepias variegata – white milkweed N Asclepias verticillata – whorled milkweed N Asclepias viridiflora – green milkweed, green comet milkweed, short green milkweed Asimina N Asimina triloba – common pawpaw Asparagus X Asparagus officinalis – garden asparagus, asparagus-fern Asperugo X Asperugo procumbens – German madwort, catchweed Asperula X Asperula arvensis – blue woodruff Asplenium N Asplenium platyneuron – ebony spleenwort N Asplenium rhizophyllum – walking fern N Asplenium ruta-muraria – wall-rue N Asplenium scolopendrium var. americanum – American Hart's-tongue fern Special Concern N Asplenium trichomanes – maidenhair spleenwort N Asplenium viride – green spleenwort Aster N Aster alpinus – alpine aster Astragalus N Astragalus adsurgens – ascending milkvetch, rattle milkvetch, standing milkvetch N Astragalus agrestis – field milkvetch, mile-vetch, cock's-head N Astragalus alpinus – alpine milkvetch N Astragalus americanus – American milkvetch N Astragalus australis – Indian milkvetch N Astragalus canadensis – Canada milkvetch, Carolina milkvetch X Astragalus cicer – chickpea milkvetch N Astragalus eucosmus – elegant milkvetch, pretty milkvetch X Astragalus glycophyllos – wild liquorice N Astragalus neglectus – Cooper's milkvetch N Astragalus tenellus – pulse milkvetch, loose-flower milkvetch At Athyrium N Athyrium filix-femina var. angustum – northern lady fern N Athyrium filix-femina var. cyclosorum – northwestern lady fern Atriplex N Atriplex dioica – thickleaf orache, saline saltbush N Atriplex glabriuscula – smooth orache, Scotland orache, glabrous orache, northeastern saltbush X Atriplex heterosperma – two-scale orache X Atriplex hortensis – garden orache X Atriplex oblongifolia – oblong-leaf orache N Atriplex patula – spear orache, spreading orache, spearscale, halberdleaf orache, common orache N Atriplex prostrata – thinleaf orache, triangle orache, fat-hen X Atriplex rosea –