1. Extending to the knee

See also: knee

• family Aspleniaceae
• family Astacidae
• family Asteraceae
• family Atherinidae
• family Athiorhodaceae
• family Athyriaceae
• family Atrichornithidae
• family Atropidae
• family Aulostomidae
• family Auriculariaceae
• family Avicenniaceae
• family Azollaceae
• family Babesiidae
• family Bacillaceae
• family Bacteroidaceae
• family Balaenicipitidae
• family Balaenidae
• family Balaenopteridae
• family Balanidae
• family Balistidae
• family Balsaminaceae
• family Bangiaceae
• family Bathyergidae
• family Batidaceae
• family Batrachoididae