Cosmarium

Class: chlorophceae

Order: Zygnematales

Family: Desmidiaceae

Genus: Cosmarium

Cosmarium is a uni-cellular fresh water desmids occurring in ponds, rich in organic decaying matter, along with other free-floating algae. Usually it occurs in abundance in mucilaginous masses along the wall of reservoirs and water tanks especially in winter'

The cell posses a distinct median constriction called sinus. This divides them in to two distinct halves called semi- cells. Which remains join together by a connecting zone called isthmus. Each semi-cell maybe circular, elliptical or oval in shape. The cells posses a three layered transversely segmented walls with vertical poles arranged in a definite pattern. A single nucleus is found in the isthmus region. There is one or more chloroplast in each semi-cell with one or two pyrenoid.

Reproduction takes place by asexual reproduction (cell division) and isogamous sexual reproduction. Sexual reproduction results formation of zygospore.

Posted in: Microbiology