1. Small blue-flowered fringed gentian of western United States (Rocky Mountains) especially around hot springs in Yellowstone National Park
   - Gentiana thermalis

Type of: fringed gentian

• genus Athrotaxis
• genus Athyrium
• genus Atrichornis
• genus Atriplex
• genus Atropa
• genus Attalea
• genus Atticus
• genus Aucuba
• genus Aulacorhyncus
• genus Aulostomus
• genus Aureolaria
• genus Auricularia
• genus Auriparus
• genus Australopithecus
• genus Austrocedrus
• genus Austrotaxus
• genus Automeris
• genus Avahi
• genus Avena
• genus Averrhoa
• genus Avicennia
• genus Ayapana
• genus Aythya
• genus Azadirachta
• genus Azolla