- Psilopsida, class Psilopsida, Psilotatae, class Psilotatae - whisk ferns; comprising the family Psilotaceae or Psilotatae: vascular plants with no roots, partial if any leaf differentiation, and rudimentary spore sacs
--1 is a kind of class
--1 is a member of Pteridophyta, division Pteridophyta
--1 has members: Psilotales, order Psilotales