Scytonema mirabile Bornet (1889: 155)

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

Scytonema mirabile Bornet (1889: 155) Fig. 75 A–L.

Thallus a felt-like blackish-green mat; filaments straight or variously flexuous, 10.5–21.0 μm broad, with solitary or geminate false-branching; sheaths wide, colourless to yellow or yellowish-brown in colour, with parallel layers. Trichomes cylindrical, widened towards the ends, towards the centre of the trichome not or slightly constricted at the cross walls, distinctly constricted towards the trichome apices. Vegetative cells isodiametric to cylindrical, 6.5–16.0 μm long × 6.3–10.5 μm broad, blue-green to olive-green in colour; apical cells widened, barrel-shaped, distinctly constricted at the cross walls, sometimes vacuolated, end cell hemispherical rounded, up to 16 μm wide. Heterocytes intercalary, isodiametric to cylindrical, 13.0–22.5 μm long × 8.1–10.7 μm broad.

Specimens examined:—Wallaby Ck at Talaroo, Einasleigh R. at Talaroo.

Other records:— Queensland: Skinner & Entwisle (2001), New South Wales: Adeline Falls, Lawson, Blue Mountains, S. Skinner & T.J. Entwisle, 2001 (NSW 627141), Swamp on road to Barokee Rest Area, Cathedral Rock Natl Park, Skinner, 2000 (NSW), Woronora R., Eckersley Ford, 11 km below Woronora Dam, Entwisle, 1999 (NSW), Mill Ck, 5 km E of Wisemans Ferry, Entwisle, 2000 (NSW), Playfair (1912), Playfair (1917); Victoria: River into Old R, 5 km W of Mt Castor, South West Natl Park, Entwisle, 1996 (MEL); Northern Territory: Wangi Falls, Litchfield Natl Park, Entwisle, 1997 (MEL).

Observations:—Growing amongst the metaphyton amongst aquatic plants in the littoral zone and in shallow offstream waterholes in tropical rivers.