Spirogyra sp. Link., 1820
The unbranched filaments consist of cylindrical cells that are nearly as broad as long or the length may be several times the breadth. The chloroplasts are ribbon-shaped spiral bands that extend from one end of the cell to the other. Each chloroplast has several pyrenoids that lie equidistant from one another in a linear series. The cell has a single nucleus surrounded by a sheath of cytoplasm and suspended in the middle of the central vaculoe by cytoplasmic strands.
Most non-flowing freshwaters.
Spirogyra is one of the commonest green algae in quiet freshwaters. The filaments are free-floating and usually intermingelw with other algae to form a slippery mass.
Accidental breakage of filaments lead to increase in number of filaments. Conjugation is anisogamous. Two strands come together with each cell contributing equally to a conjugation tube. The cell contents develop into gametes and the male gametes migrate through the conjugation tube to fuse with the female gametes in the other filament to from a zygote. The zygote eventually germinates into a new filament.
Bold, H. C., C. J. Alexopoulos & T. Delevoryas, 1987. Morphology of plants and fungi. Harper & Row, New York. (5th ed.). 912pp.
Wee Yeow Chin