Cylindrospermum Kützing ex Bornet & Flahault (1886: 249)

Mcgregor, Glenn B., 2018, Freshwater Cyanobacteria of North-Eastern Australia: 3. Nostocales, Phytotaxa 359 (1), pp. 448-450 : 448-450

Cylindrospermum Kützing ex Bornet & Flahault (1886: 249)

Type: C. majus Kützing ex Bornet & Flahault (1888: 252)

Filaments forming a fine or compact, expanded mucilaginous mat on submerged substrates, straight, slightly curved or irregularly coiled, cylindrical along their entire length or slightly narrowed towards the middle, without sheaths, but with very fine, colourless, homogeneous, diffluent mucilage, symmetrical, constricted at the cross walls. Vegetative cells cylindrical, isodiametric or longer than wide, rarely barrel-shaped or almost spherical, without aerotopes, sometimes with dispersed granules and visible chromatoplasm, pale or bright blue-green. Heterocytes terminal, arising from apical cells, ovoid, oval or conical, developing at both ends of trichomes, rarely only at the one end. Akinetes develop adjacent to heterocytes, at both ends of the trichome, usually ovate, ellipsoidal or sub-cylindrical, solitary or up to 7 in series, sometimes with sculptured outer cell wall. Cells divide crosswise and grow into the original size before the next division. Without meristematic zones, all cells capable of dividing. Reproduction by trichome fragmentation into hormogonia and by akinete production.

A widely distributed genus of 49 species known from freshwater lakes and streams and wetlands, growing in benthos, on aquatic plants and submerged woody and stony substrates. Here three species are described from north-eastern Australia; a further eight species are known from elsewhere in Australia. Bibliography: Komárek (1989), Skinner & Entwisle (2001), Komárek (2013), Komárek et al. (2014), Johansen et al. (2014).

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- Filaments <3.5 μm broad........................................................................................................................................................ C. sp. A Filaments> 3.5 μm broad...................................................................................................................................................................2 Akinetes elliptical to broadly ovate............................................................................................................................. C. licheniforme Akinetes cylindrical to cylindrical-oval, rounded at the ends ........................................................................................... C. stagnale