Ranunculus lapponicus (Lapland buttercup)

Artemisia absinthium
Artemisia campestris ssp. borealis var. borealis (field sage
Artemisia dracunculus
Artemisia ludoviciana ssp. ludoviciana (white sagebrush)
Artemisia vulgaris
Aruba
Arum maculatum
Arundinaria gigantea ssp. tecta (switchcane)
Asarum canadense (Canadian wildginger)
Asarum europaeum
Asclepias engelmanniana (Engelmann's milkweed)
Asclepias latifolia (broadleaf milkweed)
Asclepias stenophylla (slimleaf milkweed)
Asclepias subverticillata (horsetail milkweed)
Ashmore and Cartier Islands
Asparagus densiflorus
Asparagus officinalis
Asparagus officinalis (garden asparagus)
Asphodeline liburnica
Asplenium bradleyi (Bradley's spleenwort)
Asplenium exiguum (little spleenwort)
Asplenium fissum
Asplenium pinnatifidum (lobed spleenwort)
Asplenium resiliens (blackstem spleenwort)
Asplenium rhizophyllum (walking fern)
Asplenium ruta-muraria
Asplenium scolopendrium (Hart's tonguefern)
Asplenium scolopendrium var. americanum (Hart's tonguefern)
Asplenium trichomanes (maidenhair spleenwort)

Image of Ranunculus lapponicus (Lapland buttercup) 1
USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 2: 106.