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|Noun||1.||Psilopsida - whisk ferns; comprising the family Psilotaceae or Psilotatae: vascular plants with no roots, partial if any leaf differentiation, and rudimentary spore sacs|
class - (biology) a taxonomic group containing one or more orders
division Pteridophyta, Pteridophyta - containing all the vascular plants that do not bear seeds: ferns, horsetails, club mosses, and whisk ferns; in some classifications considered a subdivision of Tracheophyta