Pteris vittata.

 Marginal sori of Pteris vittata

Pteris quadriaurita

Marginal sori of Pteris quadriaurita

Systematic position Division: Filicophyta Class: Leptosporangiopsida Order: Filicales Family: Polypodiaceae Genus: Pteris Species: P.vittata (very common), P.quadriaauritia Habitat: Terrestrial

Genus: Pteris- Plant body The plant body is the sporophyte Differentiated into stem root and leaves Consists of Subterranean rhizome or stem, roots and leaves Stem (Rhizome): Stem modifies to underground rhizome. Creeping (P.vittata) or semi erect (P. cretica). Function: anchorage Leaves: Macrophyllous pinnately compound leaves. Central midrib, young leaves show circinate vernation Function: photosynthesis, some are sporophylls Root: Adventitious roots arising from rhizhome Function: anchorage and absorption Other features: Homosporous and Leptosporangiate Life cycle: Heteromorphic alternation of generation

Vegetative Reproduction Death and decay of older portion of rhizome. When the decay reaches the branching regions, the two branches separate and grow as individual plants

Sori: Spore producing structure Plant is homosporous. Sporangia are grouped in continuous sorus at the lower margins of fertile pinnules or sporophylls Marginal sorus Continous or coenosorous: many sori are closely packed It is protected by the upper indusial flap that is formed by the margins of the pinnae (false indusium) The lower or the true indusium is absent. Each sporangium produces 48 spores.

It is protected by the upper indusial flap that is formed by the curving of margins of the pinnae (false indusium) A delicate membranous structure, known as indusium also arises from the lower side placenta and covers the sorus of sporangia

Each sporangium is composed of a multi cellular stalk and a capsule. The wall of the capsule is composed of a single layer of thin walled cells. A row of specially thickened cells, known as annulus partially surrounds the capsule. At one side of the annulus, there is a stomium composed of thin walled cells. On maturity, the sporangium contains about 32 to 64 dark, walled spores in it. Spore triangular with exine and intine. Spore germination form prothallus

Gametophyte or prothallus Green, heart shaped with many rhizoids on the under side for absorption Cells are thin walled with chloroplast and therefore independent Monoecious or bisexual: Both antheridia and archegonia are present and formed on the under side Archegonia near the central notch Antheridia formed near the rhizoids Water essential for fertilization