Staurastrum

Staurastrum paradoxum

Staurastrum is a genus of algae from the group of ornamental algae ( Desmidiales ), which includes about 1200 species. It is thus one of the most species-rich algal genera.

Features

There are unicellular, unbegeißelte algae. The cells are divided by a constriction (sinus ) in two identical half-cells. The sinus is usually wide open or is a shallow constriction. The shape of the half-cells is very different depending on the type. It can be almost circular, triangular, square or polygonal. The cell wall may be provided with warts, bumps or spines and is often punctured. Often located at the corners of the half- cells radiating extensions, so that the cells act in a star shape. At each renewal sit two to four sting. In each half- cell is an axial chloroplast, which reaches into every cell elongation. Per chloroplast, a pyrenoid is usually present, rarely more.

Asexual reproduction occurs in the typical ornamental algae form. Sexual reproduction occurs by conjugation of two cells. The zygote is spherical, egg-shaped or polyhedral, and is connected to the empty cells. The wall of the zygote is staffed smooth or with long forked spines.

The size of the cells ranges from 17 to 80.

Dissemination

The genus as well as many species is cosmopolitan. Staurastrum living benthic or floating freely in all water types.

System

Some representative also in Central Europe species are:

• Aculeatum Staurastrum
• Staurastrum dickiei
• Staurastrum erasum
• Staurastrum glaber
• Staurastrum gracile
• Staurastrum pingue
• Staurastrum polymorphum
• Staurastrum punctulatum
• Staurastrum scabrum
• Staurastrum spongiosum
• Staurastrum teliferum
• Staurastrum tetracerum

Documents

• K.-H. Linne von Berg, K. Hoef -Emden, B. Marin, M. Melkonian: The Cosmos algae leader. The main freshwater algae under the microscope. Kosmos, Stuttgart 2004, p 124 ISBN 3-440-09719-6