Feature | Description |
---|---|
General Characteristics of Pteridophyta | |
Common Name | Pteridophytes |
Groups Included | Horsetails and ferns |
Uses | Medicinal purposes, soil-binders, ornamental plants |
Evolutionary Significance | First terrestrial plants to possess vascular tissues (xylem and phloem) |
Habitat | Cool, damp, shady places; some in sandy-soil conditions |
Dominant Phase | Sporophyte (differentiated into true root, stem, and leaves) |
Leaves | Small (microphylls) as in Selaginella or large (macrophylls) as in ferns |
Sporophylls | Leaf-like appendages that bear sporangia; can form strobili or cones (Selaginella, Equisetum) |
Spores | Produced by meiosis in spore mother cells; germinate to form gametophytes |
Gametophyte | Inconspicuous, small, multicellular, free-living, mostly photosynthetic thalloid (prothallus); require cool, damp, shady places |
Gametophyte Organs | Antheridia (male), archegonia (female) |
Water Requirement | Needed for fertilization; male gametes (antherozoids) transfer to archegonium |
Fertilization | Fusion of male gamete with egg in archegonium forms zygote; zygote develops into sporophyte |
Spore Types | Homosporous (similar spores), Heterosporous (macro and micro spores) |
Heterospory | Selaginella and Salvinia produce two types of spores: macrospores (female gametophytes) and microspores (male gametophytes) |
Zygote Development | Occurs within female gametophytes; precursor to seed habit, significant in evolution |
Classification |
Psilopsida – Psilotum Lycopsida – Selaginella, Lycopodium Sphenopsida – Equisetum Pteropsida – Dryopteris, Pteris, Adiantum |
Ex-situ- BIODIVERSITY-7