ludovici (A. pachypoda × A. rubra) – hybrid baneberry Ad Adenocaulon N Adenocaulon bicolor – trail-plant Adiantum N Adiantum aleuticum – western maidenhair fern N Adiantum capillus-veneris – southern maidenhair fern N Adiantum pedatum – northern maidenhair fern, five-finger fern N Adiantum viridimontanum – Green Mountain maidenhair fern Adlumia N Adlumia fungosa – Allegheny vine, climbing fumitory Adonis X Adonis annua – pheasant's-eye Adoxa N Adoxa moschatellina – moschatel, muskroot, townhall clock Ae Aegopodium X Aegopodium podagraria – goutweed, snow-on-the-mountain, goat's-foot, ground elder, bishop's weed Aesculus N Aesculus glabra – Ohio buckeye, fœtid buckeye X Aesculus hippocastanum – common horsechestnut Aethusa X Aethusa cynapium – fool's-parsley Ag Agalinis N Agalinis gattingeri – Gattinger's agalinis Endangered N Agalinis paupercula – small-flowered purple false-foxglove, small-flowered agalinis N Agalinis purpurea – purple false foxglove, large purple agalinis N Agalinis skinneriana – Skinner's agalinis Endangered N Agalinis tenuifolia – slenderleaf purple false foxglove, slenderleaf agalinis Agastache N Agastache foeniculum – anise hyssop, blue giant hyssop N Agastache nepetoides – yellow giant hyssop N Agastache scrophulariifolia – purple giant hyssop Agoseris N Agoseris glauca – pale false-dandelion, prairie agoseris, pale agoseris, pale goat-chicory, large-flowered false-dandelion Agrimonia X Agrimonia eupatoria – medicinal agrimony, church steeples, European groovebur N Agrimonia gryposepala – tall hairy agrimony, tall hairy groovebur N Agrimonia parviflora – smallflower groovebur, harvestlice agrimony N Agrimonia pubescens – soft groovebur, soft agrimony N Agrimonia striata – woodland agrimony, grooved agrimony Agropyron X Agropyron cristatum – crested wheatgrass Agrostemma X Agrostemma githago – common corncockle Agrostis ? Agrostis canina – brown bentgrass X Agrostis capillaris – colonial bentgrass, browntop, Prince Edward Island bentgrass, Rhode Island bentgrass X Agrostis gigantea – black bentgrass, redtop N Agrostis hyemalis – winter bentgrass, ticklegrass N Agrostis mertensii – northern bentgrass N Agrostis perennans – upland bentgrass, perennial bentgrass N Agrostis scabra – rough bentgrass, tickle grass, rough hairgrass, twin bentgrass N Agrostis stolonifera – creeping bentgrass, spreading bentgrass Ai Ailanthus X Ailanthus altissima – tree-of-Heaven, Chinese sumac, stinktree, varnish tree Aj Ajuga X Ajuga genevensis – Geneva bugleweed X Ajuga reptans – carpet bugleweed, common bugle, creeping bugleweed Al Alcea X Alcea pallida – pale hollyhock X Alcea rosea – hollyhock Alchemilla X Alchemilla filicaulis – thin-stemmed lady's-mantle X Alchemilla monticola – hairy lady's-mantle Aletris N Aletris farinosa – colicroot Threatened Alisma N Alisma gramineum – grass-leaved water-plantain N Alisma subcordatum – southern water-plantain N Alisma triviale – northern water-plantain