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CH 21 part 3. Phylum Polypodiophyta – The Ferns. Crozier. Reproduction: Sporophyte is conspicuous phase. Fronds, rhizomes, roots Fronds first appear coiled in crozier (fiddlehead), and then unroll and expand. Fronds often divided into segments called pinnae (singular: pinna ).
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Phylum Polypodiophyta – The Ferns Crozier • Reproduction: • Sporophyte is conspicuous phase. • Fronds, rhizomes, roots • Fronds first appear coiled in crozier (fiddlehead), and then unroll and expand. • Fronds often divided into segments called pinnae (singular: pinna).
Phylum Polypodiophyta – The Ferns Sorus covered by indusium • Reproduction: • Sporangia stalked. • May be scattered on lower leaf surface, confined to margins, or found in discrete clusters called sori (singular: sorus). • Sori may be protected by indusia (singular: indusium). • With row of heavy-walled, brownish cells = annulus • Annulus catapults spores out of sporangium.
Phylum Polypodiophyta – The Ferns • Prothalli are one cell thick, and have archegonia and antheridia. • Zygote develops into young sporophyte. • Gametophyte, or portion of it, dies and leaves sporophyte growing independently. • Reproduction: • Meiosis forms spores in sporangia. • Spores released and grow into gametophytes called prothalli (singular: prothallus).
Phylum Polypodiophyta – The Ferns Reproduction:
Phylum Polypodiophyta – The Ferns • Devonian, 375 million years ago - Possible ancestors of ferns • Resemble ferns in growth habit, but look more like whisk ferns Possible ancestors: Aglaophyton and Psilophyton Fossil relatives of ferns:
Phylum Polypodiophyta – The Ferns • Fossil relatives of ferns • Carboniferous, 320-250 million years ago - Tree ferns abundant • Seeds found on some of fossil tree ferns.
Phylum Polypodiophyta • Human and ecological relevance: • House plants • Function well as air filters • Outdoor ornamentals • Cooked rhizomes as food • Folk medicine • Fronds used in thatching for houses. • Basketry and weaving
Fossils • A fossil - Any recognizable prehistoric organic object preserved from past geological ages. • Conditions of formation almost always include quick burial and an accumulation of sediments. • Hard parts more likely preserved than soft parts.
Fossils • If air space remains - Mold • If silica fills space - Cast • Compression - Objects buried by layers of sediment and overlying sheer weight compresses them to thin film of organic material and an outline. • Image of an impression = imprint • Coal is a specific type of compression. • Molds, casts, compressions, and imprints: • After being buried in sediment and hardened into rock, organic material slowly washed away. Compression fossil
Fossils • Coprolites - Dung of prehistoric animals and humans • Unaltered fossils - Organisms fell into oil or water that lacked oxygen and did not permit decay. Petrified wood • Petrifactions - Uncompressed rock-like material in which original cell structure has been preserved • Chemicals in solution infiltrate cells and cell walls, where they crystallize and harden, preserving original material.
Review Introduction Phylum Psilotophyta – The Whisk Ferns Phylum Lycophyta – The Ground Pines, Spike Mosses and Quillworts Phylum Equisetophyta – The Horsetails and Scouring Rushes Phylum Polypodiophyta – The Ferns Fossils