Chapter 17 Phylum Pteridophyta Majority of Pteridophyta are ferns -
Two kinds of sporangia in ferns Large and contain many spores -
Arise from a single cell Tapetum is two-cells-thick nutritive tissue Annulus drying results in catapult-like discharge of spores Pteridophyta Ophioglossales and Marattiales Heterosporous leptosporangiate ferns Marsileales and Salviniales (water ferns) Whisk ferns (Eusporate and rootless) Order Ophioglossales 3 genera (Botrychium, Ophioglossum) Each leaf has a vegetative portion or blade and a fertile segment -
Gametophytes resemble those of Psilotales Marattiales Look more like “ferns” Six living genera of 200 species Filicales Homosporous leptosporangiate 10,500 species Fronds are megaphylls of sporophyte Fronds are divided into pinnae along rachis -
Sporophyte is perennial stage in ferns Filicales Sporangia occur in clusters called sori in many genera Filicales Filicales Bisexual gametophyte is heart-shaped prothallus with rhizoids Archegonia near notch in heart Antheridia near rhizoids -
Filicales Gametophyte is short-lived -
Produce gemmae Water ferns Heterosporous leptosporangiate ferns Marsilcales and Salviniales Water ferns -
Azolla contains cynanobacteria Psilotales Whisk ferns with two genera, Psilotum and Tmesipteris Rootless and eusporangiate -
Equisitales Genus Equisetum, horsetails Jointed stems and rough textures Homosporous Sporangia are borne in groups of 5-10 along the margin of umbrella-like structures called sporangiophores, which are clustered into stroboli Green, free-living gametophytes are bisexual or male |