ALGAE

VOLVOX ALGAE

Gloeotrichia occurs as mucilaginous balls or mass floating on the surface of the stagnant waters. Colonies are also found as epiphytes on aquatic weeds growing near the margins of ponds and pools

Rivularia commonly occurs in aquatic habitats, as also on damp soil near river bed, between mosses on earth, moist rocks and in flowing waters. It is epiphytic, occurring on Nitella and other submerged stems and leaves of water plants.

The genus Scytonema is usually found in sub-aerial habitats such as damp walls, brick-work, bark of the trees, etc. Filaments are interwoven to form a felt-like mass of considerable extent. Few species grow best on damp soil and others on the dripping surfaces of rocky cliffs.

Nostoc commonly occurs in abundance after the first few rains. It is terrestrial as well as aquatic. It is collected from water pools, paddy fields, waterlogged soil, moist rocks, stagnant water, etc. It is known to occur as epiphyte on aquatic weeds and endophytically inside Cycas coralloid roots, Azollaa fern, Blasia and Anthoceros-bryophytes and form lichens in association with fungal members

One can hardly miss Oscillatoria when on a collection trip. It is almost cosmopolitan and occurs abundantly on moist rocks, cliffs, damp soil, muddy banks of streams, ponds, surface of the water reservoirs, sewage ponds, etc. A few species are marine and float on the surface.

Species of Polysiphonia are exclusively marine.  These are most commonly found along the Atlantic  and Pacific coasts, in littoral and sub-littoral regions.  A few species occur as epiphytes on mangroves or  brown seaweeds. A small number of species are  also found along the Indian coasts. 

Ceramium occurs very commonly between tide levels and also in deeper waters. The species of the genus are especially abundant in Mediterranean coast. The commonest Indian species include Ceramium cruciatum, C. elegans, C. strictum, C. subdichotomum, etc.

Batrachospermum is commonly found in fresh waters. The filaments are attached to stones in slow moving waters of rivers and streams or on the margins of the lakes.

Sargassum is marine in habitat and remains restricted to tropical seas, mainly of southern hemisphere. In India, species of this genus are found along the east coast, west coast, and Andman and Nicobar islands.