• Apocynum androsaemifolium L., Spreading dogbane, Native, Common, Photos Phytoimages, USDA_Plants

• Apocynum cannabinum L., Indian hemp, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Apocynum X floribundum Greene, Dogbane, A hybrid between A. androsaemifolium and A. cannabinum, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias engelmanniana Woodson, Engelmann's milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias hallii A. Gray, Hall's milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias incarnata L., Swamp milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias pumila (A. Gray) Vail, Plains milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias speciosa Torr., Showy milkweed, Common milkweed, Native, Common, Photos Phytoimages, USDA_Plants

• Asclepias stenophylla A. Gray, Slimleaf milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias subverticillata (A. Gray) Vail, Horsetail milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Asclepias viridiflora Raf., Green comet milkweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

Araceae

• Lemna minor L., Common duckweed, Synonyms: Lemna turionifera Landolt, Native, Common, Photos Phytoimages, USDA_Plants

• Lemna trisulca L., Star duckweed, Native, Larimer Co., Photos Phytoimages, USDA_Plants

• Wolffia borealis (Engelm.) Landolt & Wildi ex Gandhi, Wiersema & Broullet, Northern watermeal, Native, Larimer Co., Photos Phytoimages, USDA_Plants

Araliaceae

• Aralia nudicaulis L., Wild sarsaparilla, Native, Uncommon, Photos Phytoimages, USDA_Plants

Asparagaceae

• Asparagus officinalis L., Asparagus, Garden asparagus, Introduced, Rare, Photos Phytoimages, USDA_Plants