Aphanizomenon Morren ex Bornet & Flahault (1888: 180)

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

Aphanizomenon Morren ex Bornet & Flahault (1888: 180)

Type: A. flosaquae Ralfs ex Bornet & Flahault (1886: 241)

Filaments planktonic, solitary, in a few species joined into fascicle-like, microscopic or macroscopic colonies with trichomes oriented in parallel; trichomes straight or slightly bent, cylindrical or sharply or continually tapered towards the ends, ± constricted at the cross walls, sometimes with diffluent and colourless mucilage trichomes uniseriate, trichomes sub-symmetric, with intercalary heterocytes, which are sub-symmetrically localized in fully developed trichomes. Vegetative cells cylindrical or barrel-shaped, isodiametric or slightly shorter or longer than wide, pale blue-green or blue-green, with aerotopes, several species facultatively develop aerotopes. Heterocytes few (1–3 per trichome), intercalary, barrel-shaped or cylindrical with rounded or obtuse ends. Akinetes typically oval to long, cylindrical with rounded ends, developing paraheterocytically, solitary or in short rows, close to heterocytes or slightly distant from them, usually in an asymmetrical position. Reproduction by trichome dissociation and by akinetes.

A widely distributed genus of 19 species known from freshwater lakes and reservoirs and rivers. One species is known from north-eastern Australia. The traditional genus Aphanizomenon is heterogeneous ( Komárek & Mareš 2012). Over the past decade, several species traditionally belonging to Aphanizomenon have been transferred to new genera based on updated phylogenetic information ( Cuspidothrix , Chrysosporum , Sphaerospermopsis ). Bibliography: Baker (1991), Baker & Fabbro (2002), Li et al. (2000, 2003), Rajaniemi et al. (2005a, 2005b), Komárek & Komárková (2006), Komárek & Mareš (2012), Zapomělová et al. (2012), Cirés & Ballot (2016), Komárek (2016).