Holotype species: Clastidium setigerum O. Original publication and holotype designation: Kirchner, O. Request PDF. Description: Unicellular; solitary elongated cells, rarely grouped together, joined more or less perpendicularly by one basal end to the substrate, usually to filamentous algae or submerged aquatic plants. Cells always polarized, attached to the substrate by the narrowed mucilaginous pad, on the apical end also narrowed and prolonged into thin mucilaginous hair-like string sometimes long ; cell-form widely oval, ellipsoidal, ovoid or pear-shaped, rarely slightly club-shaped.
Around cells sometimes thin, mucilaginous, often diffluent, colorless sheaths pseudovaginae , which open at the top during the cell division. Cell content pale blue-green, usually without visible granules, always without aerotopes.
Cells divide first asymmetrically in their apical parts, later successively or almost spontaneously always perpendicular to the long axis of a cell, sometimes forming a row of daughter cells exocytes at the apical end, from which they escape and join again to the substrate; sometimes remains the basal part of the cell undivided and further divisions proceed successively only in the upper part of the cell.
The basal sterile part can grow and divide again at its apical end. Whole elongated cell rarely divides into daughter cells - exocytes. Young cells develop first with rounded apex, apical mucilaginous strings form later.. All species are known from clear, streams or stagnant mountain waters, the commonest and probably cosmopolitan C. One species is known from Arctic Canadian lakes. Information contributed by: J. The most recent alteration to this page was made on by M.
An updated classification of cyanobacterial orders and families based on phylogenomic and polyphasic analysis Review. Journal of Phycology 59 1 : Verification of Data Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
