Definition that contains type a
- lycopodium type and sole genus of the Lycopodiaceae; erect or creeping evergreen plants often used for Christmas decorations
- phoeniculus type and only genus of the family Phoeniculidae
- genus selaginella type and sole genus of the Selaginellaceae; evergreen moss-like plants: spike moss and little club moss
- genus menura type and sole genus of the family Menuridae
- genus isoetes type and genus of the Isoetaceae and sole extant genus of the order Isoetales
- genus steatornis type and sole genus of the family Steatornithidae
- genus eschrichtius type and sole genus of the Eschrichtiidae
- genus symplocus type and sole genus of Symplocaceae including sweetleaf
- genus odontaspis type and sole genus of Carchariidae: sand sharks
- genus xenosaurus type and sole genus of Xenosauridae: slender-bodied Mexican lizards having the upper surface covered with tiny granules and tubercles