Definition that contains type a
- lycopodium type and sole genus of the Lycopodiaceae; erect or creeping evergreen plants often used for Christmas decorations
- genus liopelma type and sole genus of the family Leiopelmatidae
- genus canna type and sole genus of the Cannaceae: perennial lily-like herbs of New World tropics
- clethra type and sole genus of the Clethraceae; deciduous shrubs or small trees: white alder, summer-sweet
- sciadopitys type and sole genus of Sciadopityaceae; Japanese umbrella pines
- trichechus type and sole genus of the Trichechidae
- genus tyto type and only genus of the family Tytonidae
- genus sphyraena type and sole genus of the Sphyraenidae: barracuda
- isoetes type and genus of the Isoetaceae and sole extant genus of the order Isoetales
- steatornis type and sole genus of the family Steatornithidae