Nodularia Mertens ex Bornet & Flahault (1886: 243)

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

Nodularia Mertens ex Bornet & Flahault (1886: 243)

Type: N. spumigena Mertens ex Bornet & Flahault (1888: 245)

Filamentous; filaments solitary or in groups or clusters, rarely in mats, isopolar, unbranched, straight, curved, coiled or irregularly spirally coiled with fine, diffluent mucilage, opened at both ends. Trichomes uniseriate, cylindrical, rarely short and slightly attenuated at the ends of mature trichomes, constricted at the cross walls, metameric, with heterocytes regularly spaced. Vegetative cells shortly barrel-shaped, generally broader than long, aerotopes present in planktonic species. Cell content yellowish, pale olive-green or blue-green in colour. Heterocytes generally the same shape as vegetative cells, sometimes slightly smaller or larger. Akinetes shortly barrel-shaped, shorter than wide, or spherical, developing apoheterocytically. Cells divide crosswise to the trichome axis, growing to their original size before the next division, all cells capable of division, without meristematic zones. Reproduction by hormogonia, dissociation of trichomes, and by akinete production.

A widely distributed genus of 22 species including planktonic and benthic species, known from freshwater lakes and reservoirs, rivers, estuaries and inland saline lakes. Here three species are described from north-eastern Australia. Bibliography: Šmarda et al. (1988), Komárek et al. (1993), Bolch et al. (1999), Vigna et al. (2001), Lyra et al. (2005), Krüger et al. (2009), Hašler et al. (2011), Řeháková et al. (2014).

1. - 2. - Trichomes planktonic, with aerotopes............................................................................................................................ N. spumigena Trichomes benthic or periphytic, without aerotopes..........................................................................................................................2 Vegetative cells 1.5–2.8 μm long × 4.0–5.5 μm wide.................................................................................................... N. harveyana Vegetative cells 2.0–4.8 μm long × 8.2–11.5 μm wide .......................................................................................................... N. willei