Dolichospermum (Ralfs ex Bornet & Flahault) Wacklin, Hoffmann & Komárek (2009: 60)

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

Dolichospermum (Ralfs ex Bornet & Flahault) Wacklin, Hoffmann & Komárek (2009: 60)

Type: D. flosaquae (Brébisson ex Bornet & Flahault) Wacklin, Hoffmann & Komárek (2009: 60)

Filaments planktonic, solitary or aggregated into floccose masses; trichomes isopolar, metameric with respect to the position of heterocytes, straight, flexuous, circinate, spirally coiled or irregularly twisted, constricted at the cross walls, without firm sheaths, generally with fine diffluent mucilage. Vegetative cells spherical, ellipsoidal, barrel-shaped, quadrate or cylindrical, with aerotopes. Apical cells undifferentiated, morphologically similar to the vegetative cells. Heterocytes intercalary, solitary, exceptionally in pairs; developing from vegetative cells in ± metameric position. Akinetes spherical to cylindrical in shape, developing paraheterocytically, rarely adjacent to heterocytes, generally separated from them by one or more cells, solitary or in series. Mature akinetes usually three or more times larger than vegetative cells.

A widely distributed genus of 45 species known from the plankton of freshwater lakes, reservoirs, rivers and estuaries. Here nine species are described from north-eastern Australia. Planktonic species with aerotopes, previously considered within the genus Anabaena have recently been transferred to Dolichospermum ( Wacklin et al. 2009) . It is likely that more revisions will be made in the future. Bibliography: Baker (1991), Li & Watanabe (2000, 2001), Fergusson & Saint (2000), Lyra et al. (2001), Baker & Fabbro (2002), Gugger et al. (2002a, 2002b), Rajaniemi et al. (2005a, 2005b), Zapomĕlová et al. (2007, 2010), Komárek & Zapomĕlová (2007, 2008), Wacklin et al. (2009), Andreja et al. (2015), Komárek (2016), Li et al. (2016a, 2016b).

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Filaments straight or slightly flexuous...............................................................................................................................................2 Filaments regularly or irregularly coiled............................................................................................................................................4 Filaments <6 μm broad.......................................................................................................................................................... D. affine Filaments > 6 μm broad......................................................................................................................................................................3 Akinetes spherical to broadly ovate ..................................................................................................................................... D. smithii Akinetes oblong-ovate or oblong with conical ends ................................................................................................ D. planktonicum Filaments regularly screw-like coiled................................................................................................................................................5 Filaments irregularly coiled................................................................................................................................................................7 Akinetes oval to cylindrical................................................................................................................................................................6 Akinetes cylindrical reniform...................................................................................................................................... D. perturbatum Vegetative cells globose, 8.0–12.0 μm in diameter........................................................................................................... D. crassum Vegetative cells spherical, (4.0–) 7.0–9.0 μm long × 6.0–8.5 μm broad ......................................................................... D. spiroides Vegetative cells> 5 μm in diameter .................................................................................................................................. D. circinale Vegetative cells <5 μm in diameter...................................................................................................................................................8 Akinetes cylindrical, slightly arcuate, solitary or up to two in series, adjacent to or remote from the heterocytes.... D. helicoideum Akinetes cylindrical reniform, solitary or in pairs, remote from the heterocytes............................................................ D. flosaquae