Pteridophytes are a group of primitive vascular plants that include Lycopods (club mosses), Sphenopsids (horsetails, shown left), and ferns (shown, right). These plants reproduce with spores that germinate only in moist areas; they also reproduce using rhizomes (underground stems). Pteridophytes evolved during the Devonian and were mostly low-growi... Found on http://www.enchantedlearning.com/subjects/dinosaurs/glossary/