Hapalosiphon hibernicus

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

Hapalosiphon hibernicus West & G.S.West (1896: 163) Fig 28. A–D.

Filaments solitary, or in small clusters amongst other algae, blue-green to olive-green in colour; richly branched, flexuous to irregularly coiled (5–) 7.5–9.0 μm wide. Branches erect, vertically divaricate, usually of the same diameter as the main filament. Sheaths thin, colourless to slightly yellow-brown in colour, sometimes thickened in mature filaments. Trichomes cylindrical, clearly constricted at the cross walls, particularly in older filaments, branches less so. Vegetative cells cylindrical, ± isodiametric or up to 4 × longer than broad, 6.5–17.3 μm long × 3.5–7.5 μm wide; apical cells rounded. Heterocytes cylindrical, up to 2 × longer than broad, 7.5–9.0 μm long × 3.5–6.5 μm wide.

Specimens examined:— Little R. at Gulf Development Rd .

Other records:— Victoria: Darling (1982), Entwisle (1994).

Observations:—Observed growing amongst filamentous algae and submerged aquatic vegetation in the littoral zone of an acidic tropical coastal river. Known from clear water, peaty habitats throughout the temperate zone (Komárek 2013).