Macrospermum volzii (Lemmermann) Komárek (2008: 81)

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

Macrospermum volzii (Lemmermann) Komárek (2008: 81) Figs. 46 A–E, 47 A–B .

Basionym: Anabaena volzii Lemmerman (1905: 153)

Filaments flexuous to irregularly coiled, forming fine microscopic mats, later macroscopic, spreading, occasionally in columnar formations; with fine, colourless, diffluent mucilage, constricted at the cross walls. Vegetative cells isodiametric, cylindrical, up to 2 × longer than broad, 4.5–14 μm long × 4.0–5.8 μm wide; contents homogenous, without aerotopes; apical cells conically narrowed, bluntly pointed or rounded. Heterocytes intercalary, cylindrical, 2–3 × longer than broad. Akinetes generally single, adjacent to heterocytes, mostly on one side, elliptical, 1.5–2.5 × longer than broad, with smooth brown epispore, (20–) 32–48 μm long × (13–) 15–20 μm broad.

Specimens examined:—Palmer R. at NESP Purple.

Observations:—Growing in mucilaginous colonies on sandy substrates in the littoral areas and backwaters of a tropical river and associated floodplain waterholes. Pantropical distribution including Asia, and Central and South America. Compare with M. unisporum (Gardner) Komárek , which differs little from M. volzii in terms of morphology and ecology.

Other records:— Queensland, Baker & Fabbro (2002).

NOSTOC

Figures

FIGURE 47. A–B Mats of Macrospermum volzii growing on soft sandy sediments.