N Antennaria pulcherrima – showy pussytoes, handsome pussytoes N Antennaria rosea – rosy pussytoes, pink everlasting N Antennaria subviscosa Anthemis X Anthemis arvensis – corn chamomile, field chamomile X Anthemis cotula – mayweed, stinking chamomile, fœtid chamomile, dog fennel, stinking mayweed X Anthemis tinctoria – golden chamomile Anthoxanthum X Anthoxanthum odoratum – sweet vernalgrass, sweetgrass Anthriscus X Anthriscus cerefolium – common chervil X Anthriscus sylvestris – wild chervil, woodland chervil, cow parsley, beak-chervil Anthyllis X Anthyllis vulneraria – kidney vetch, lady's fingers Antirrhinum X Antirrhinum majus – common snapdragon X Antirrhinum orontium – lesser snapdragon Ap Apera X Apera interrupta – dense silky bentgrass, interrupted bentgrass, interrupted windgrass X Apera spica-venti – silky bentgrass Apios N Apios americana – American groundnut, Indian potato, wild bean, potato-bean Aplectrum N Aplectrum hyemale – puttyroot Apocynum N Apocynum androsaemifolium – spreading dogbane N Apocynum cannabinum – Indian hemp, clasping-leaf dogbane, prairie dogbane, velvet dogbane, amyroot N Apocynum sibiricum – clasping-leaved dogbane N Apocynum × floribundum (A. androsaemifolium × A. cannabinum) – intermediate dogbane, bitter dogbane Aq Aquilegia N Aquilegia brevistyla – small-flowered columbine N Aquilegia canadensis – Canadian columbine, red columbine X Aquilegia vulgaris – European columbine, garden columbine, culverwort, capon's feather Ar Arabidopsis X Arabidopsis thaliana – mouse-ear cress, wall-cress Arabis N Arabis alpina subsp. alpina – alpine rockcress X Arabis alpina subsp. caucasica – wall rockcress, grey rockcress N Arabis arenicola var. arenicola – arctic rockcress N Arabis arenicola var. pubescens – sand rockcress N Arabis canadensis – sicklepod N Arabis divaricarpa – limestone rockcress N Arabis drummondii – Drummond rockcress N Arabis glabra – tower-mustard N Arabis hirsuta var. adpressipilis – hairy rockcress, creamflower rockcress N Arabis hirsuta var. pycnocarpa – creamflower rockcress N Arabis holboelli var. retrofracta – Holboell's rockcress N Arabis holboelli var. secunda – bristly-leaved rockcress ? Arabis kamchatica – lyreleaf rockcress (species status disputed) N Arabis laevigata – smooth rockcress N Arabis lyrata – lyreleaf rockcress N Arabis shortii – Short's rockcress Aralia X Aralia elata – Japanese Angelica-tree, Chinese Angelica-tree N Aralia hispida – bristly spikenard, bristly sarsaparilla, dwarf elder N Aralia nudicaulis – wild sarsaparilla, small spikenard N Aralia racemosa – American spikenard, Indian-root, life-of-man, petty morel X Aralia spinosa – Hercules' club, Devil's walkingstick, prickly ash, Angelica tree, toothache tree Arceuthobium N Arceuthobium americanum – pine mistletoe, American mistletoe, lodgepole pine dwarf mistletoe N Arceuthobium pusillum – dwarf mistletoe, eastern dwarf mistletoe Arctagrostis