1. Members of this group are most primitive living vascular plants.
2. The main plant body is a sporophyte. It is differentiated into root, stem and leaves.
3. Plants (sporophyte) reproduce by spores formed in sporangia. Sporangia develop either on the ventral surface or in the axil of leaves.
4. Plants may be homsoporous or heterosporous. The development of sporangium may be of eusporangiate (when develop from group of initials) or leptosporangiate. (When develop from a single initial) type.
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5. Spores develop into a multi-cellular gametophytic body called prothallus – a thalloid structure. It is independent and chlorophyllous. It bears male reproductive organs called antheridia and female reproductive organs called archegonia. Reproductive organs are multi cellular and jacketed.
6. Water is essential to effect fertilization as male reproductive units are flagellated and motile.
7. Seed formation never takes place in living pteridophytes.
8. An embryo develops in situ after fertilization and the sporophyte remains attached to the gametophyte till the development of root.
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9. Plants show clear alternation of generations. The sporophyte and gametophyte are independent of each other.
DRYOPTERIS (SHIELD FERN)
Systematic Position
Kingdom: Plantae
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Division – Ptcridophyta
Class – Filicineae
Order – Filicales
Family – Polypodiaceae
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Genus – Dryopteris
(About 150 species)
Occurrence
Dryopteris, commonly known as “Male fern” or “Shield fern”, is a perennial, terrestrial and rhizomatous herb. It is widely distributed all over the world. They grow- abundantly in cool, shady, moist places, both in the hills and in the plains.