1. Growing on or living among rocks
   - saxicolous, saxatile, rupestral, rupicolous

See also: saxicolous plant

• 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
• genus Babesia
• genus Babyrousa
• genus Baccharis
• genus Bacillus
• genus Bacteroides
• genus Baiomys
• genus Bairdiella
• genus Balaena
• genus Balaeniceps
• genus Balaenoptera
• genus Balanus