Anabaena inaequalis Bornet & Flahault (1886: 231)

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

Anabaena inaequalis Bornet & Flahault (1886: 231) Fig. 37 A–B .

Filaments benthic, jointed into prostrate mats, less commonly tychoplanktonic; trichomes straight or slightly flexuous, sometimes in parallel fascicles, constricted at the cross walls, not attenuated towards the ends. Vegetative cells shortly barrel-shaped, isodiametric or shorter or longer than wide, (2.0–) 5.5–8.5 μm long × 4.0–5.5 μm wide, ± aerotopes; apical cells rounded to rounded conical. Heterocytes spherical to cylindrical ellipsoidal, intercalary, solitary, 5.5–8.0 (– 10.5) μm long × 4.5–5.5 μm broad. Akinetes cylindrical, as broad, or slightly broader than vegetative cells, solitary or rarely in series, remote from heterocytes, 5.5–11.0 (–22) μm long × 5–8 μm broad, with smooth, colourless exospore.

Specimens examined:—Atkinson Dam, Balonne R. at Kurray, Balonne R. at St George, Bjelke-Petersen Dam, Borumba Dam, Burnett R. at Jones Weir, Burnett R. at Kirar Weir, Burnett R. at Ned Churchward Weir, California Ck at Gavin Way, Culgoa R. at Cubbie, Culgoa R. at Whyenbah, Fitzroy R. at Glebe Weir, Moogerah Dam, Home Beach Swamp at North Stradbroke Is., Sheepstation Ck at Kilcoy-Murgon Rd, Wuruma Dam.

Other records:— New South Wales: Braidwood Lagoon, Braidwood, V. May, 1968 (NSW 616150), River Murray at Heywoods, Torrumbarry, Swan Hill, Euston, Sullivan et al. (1988); Victoria: Watermeadow, Portland Aerodrome, S. Skinner, 2001 (NSW 627309), Yan Yean Res., Hardy (1907); South Australia: River Murray at Murtho, Blanchetown, Lake Alexandrina at Goolwa, Warren Res., Baker (1991).

Observations:—Australian populations have been reported from the benthos, mostly associated with soft fine sediments, and less commonly from the plankton of lakes and reservoirs. Baker (1991) describes A. inaequalis from the plankton, with or without aerotopes, not joined together into colonial fascicles, but lacking mucilage.

Figures

FIGURE 37. A–B Anabaena inaequalis; C–F Anabaena torulosa. Scale bars = 20 μm