I. Cryptogamia, Linn.—Cryptogams or Flowerless Plants.
Acotyledones, Jussieu.—Exembryonatae or Arhizae, Richard; Agamae or Atheogamae, Auctorum; Nemeae, Fries.
Characters.—Sexual organs, and, consequently, flowers and true seeds, absent. Reproduction taking place either by spores, which are enclosed in cases called thecae, or imbedded in the substance of the plants; or else by a mere dissolution of the utricles of cellular tissue. Spores destitute of embryo and cotyledons, germinating at no fixed point, but at any part of their surface.