Scytonema

Scytonema crispum

Scytonema is a genus of the tribe of cyanobacteria ( blue-green algae ).

Description

Scytonema is spurious branched, mostly blue-green to brown, einzellreihige filaments ( diameter of 8 to 70 microns ) with cylindrical cells containing as all bacterial cells neither nuclei nor plastids. Each thread is in its own gelatinous sheath. The false branch is concluded by intercalary growth. This creates a loop in the thread, which bursts forth from the gelatinous sheath, usually due to a dying individual cells. So typical of this kind two side branches arise at one point. Regularly can be found in the threads and at the ends of colorless, thick-walled cells. It is Heterozysten that serve the biological nitrogen fixation.

Reproduction

Asexual reproduction occurs by wenigzellige, able to creep thread fragments, called hormogonia.

Sexual reproduction is absent in all cyanobacteria.

Dissemination

Scytonema lives on stones at the bottom of standing and flowing waters, but also on aquatic plants. Some species survive occasional drying up of the waters. Few species live in hot springs. They are also found in damp stones. The " ink strokes " over a large area occurring on limestone rocks in the mountains are formed in part of this genus.

Types (selection)

• Scytonema amplum
• Scytonema hofmanii
• Scytonema myochrous
• Scytonema ocellatum
• Scytonema velutinum

Swell

• Karl -Heinz Linne von Berg, Kerstin Hoef -Emden, Birger Marin, Michael Melkonian: The Cosmos algae leader. The main freshwater algae under the microscope. Franckh Cosmos, 2006, ISBN 3-440-09719-6.