1. Eurasian subspecies of tundra swan; smaller than the whooper
   - Bewick's swan

Type of: Cygnus columbianus, tundra swan

• genus Arundinaria
• genus Arundo
• genus Arvicola
• genus Asarum
• genus Ascaphus
• genus Ascaridia
• genus Ascaris
• genus Asclepias
• genus Ascophyllum
• genus Asimina
• genus Asio
• genus Aspalathus
• genus Asparagus
• genus Aspergillus
• genus Asperula
• genus Asphodeline
• genus Asphodelus
• genus Aspidelaps
• genus Aspidiotus
• genus Aspidistra
• genus Aspidophoroides
• genus Aspis
• genus Asplenium
• genus Astacus
• genus Aster