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88, Sulapnil, WEDNECD, PRACTICAL 2, Study of Nostoc, ssification:, inguom: Plantae, Subkingdom: Cryptogams, Division: Cyanophyta, Class: Cyanophyceae, Order: Nostocales, Family: Nostocaceae, Genus: Nostọc, ccurrence:, Nostoc is a terrestrial or fresh water aquatic blue green alga. It grows, heridium, widely in ponds, pools, rivers, streams, road side puddles, moist soil and, rocks. It is usually found in paddy fields. It is an endophytic, i.e. found, inside the thallus of Anthoceros, pockets of Azolla and coralloid roots of, Cycas., Vegetative Struetures: (Fig. la-b), 1. Nostoc thallus is found in the form of spherical ball like colony,, which is bluish green in colour., 2. Nostoc colony is gelatinous with many straight or twisted filaments., 3. A number of rounded cells arranged in a chain or in beaded form are, pores, known as trichome, which is surrounded by its gelatinous sheath, called filament., 4. All vegetative cells in the filament are uniform in size and shape., 5. Some cells of filament are larger in size and thick-walled, called heterocysts., 6. Heterocysts are generally terminal or intercalary., 7. Heterocyst performs function of nitrogen fixation and reproduction., Page 3, REDMI NOTE 8 PRO, Handpook of Ptucal Botany of B. Sc. I, AI QUAD CAMERA