Science magazines
- Ash Meadows Sunray
- Ash-gray Indian Paintbrush
- Ashy Dogweed
- Asplenium Fragile var. insulare
- Asplenium-leaved Diellia
- Atlantic Salt Marsh Snake
- Attwater's Greater Prairie Chicken
- Audubon's Crested Caracara
- Auerodendron Pauciflorum
- Aupaka (Isodendrion hosakae)
- Aupaka (Isodendrion laurifolium)
- Aupaka (Isodendrion longifolium)
- Autumn Buttercup
- Avon Park Harebells
- Bachman's Warbler
- Baker's Larkspur
- Bakersfield Cactus
- Banbury Springs Limpet
- Bariaco
- Barneby Reed-mustard