A widely used classification of vascular plants has recognized four divisions: Psilopsida, Lycopsida, Sphenopsida and Pteropsida1. The first three have been erected in the course of time out of Jeffrey's2,3,5,5a original Lycopsida. The fourth has not been changed from Jeffrey's2,4,5,5a original Pteropsida, and is further subdivided into Filicineae (ferns) and Spermatophyta (seed plants)—both very large groups. The three divisions and these two subdivisions make five groups of plants widely recognized as distinct groups, though accorded a variety of taxonomic ranks.