Pteridophyte

Pteridophyte, class of plants that produce spores and have roots, stems, and leaves. Having vascular tissue places pteridophytes in the division, or phylum, Tracheophyta. Among other plants, the class includes ferns, horsetails, club mosses, and numerous species known from fossils. The pteridophyte's life cycle is one of alternating generations and asexual (with spores) and sexual (with egg and sperm) reproduction. Spores released from spore cases develop into a plant unlike the parent. This second form develops male and female reproductive organs. These produce eggs and sperm that unite to begin the first form of the plant. Pteridophytes that lived millions of years ago are the source of today's coal.