Rivularia
Rivularia is a genus of cyanobacteria of the familia Rivulariaceae.
Rivularia is found growing on submerged stones, moist rocks and on damp soils near the riverside. The alga is found in colonies and the trichomes are radially arranged within a colony, with each trichome wholly or partially surrounded by a gelatinous sheet. The trichomes have a basal heterocyst. Each trichome has a narrow aptical portion which is whip or tail like consisting of a row of small cells. Akinetes are absent in Rivularia. Rivularia multiplies with the aid of hormogonia and heterocyst.