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Continuing Trends in Plant Evolution • Reduction of water-dependent gametophyte • Vascular tissue – improved water/food • transport More efficient roots, stems, leaves * Tissues * Stomates Green: all these are in sporophyte Reduction of gametophyte Specialization in sporophyte Vascular tissue • • • • In sporophyte Interconnects all plant organs Xylem - water Phloem - sugar Complex leaves • Tissues • Stomates Plant classification review • Bryophytes – no seeds, no roots, no vascular * Mosses, liverworts, hornworts • Seedless, vascular plants – no seeds * Ferns, horsetails, club mosses, whisk ferns • Gymnosperms - seeds & cones * Conifers, cycads, ginkgo, gnetophytes • Flowering plants – seeds, flowers & fruits * Primitive, Monocots, Dicots Seedless Vascular Plants • • • • Ferns, horsetails, club mosses, whisk ferns Sporophyte dominant Gametophyte small but still tied to water Dominant plants from late Devonian through early Permian * Equatorial coal forests • Today somewhat marginal, but successful • Heterospory in some (next time) Gametophyte Fern Life Cycle Sporophyte Fern gametophytes … Mature fern sporophyte … … with young sporophytes … with clusters of sporangia Whisk Fern, Psilotum Club moss, Lycopodium Horsetail, Equisetum Carboniferous (-300 my) coal forest model