Scytonema subtile Möbius (1892: 448)

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

Scytonema subtile Möbius (1892: 448) Figs. 77 A–E , 78 A–F.

Filaments solitary amongst other algae, or forming small unstructured clusters, 14–17 (–21) μm wide, with geminate false-branching; branches narrowed at the base, widened towards the ends. Sheath wide, initially colourless, and later yellow to brown in colour, parallely lamellated. Trichomes cylindrical, narrowed in older parts not constricted at the cross walls, continually widened towards the ends and distinctly constricted. Vegetative cells long cylindrical in older parts of the filaments, 11.5–19.5 μm long × 1.8–5.0 (–6.5) μm wide, towards the ends shortened, isodiametric to shortly barrel-shaped, 3.5–5.5 μm long × (5.0–) 7.0–9.5 (–11.5) μm wide; apical cells widely rounded. Heterocytes ± spherical, barrel-shaped to cylindrical, 11.0–20.5 μm long × 6.0–7.5 (–12.0) μm wide.

Specimens examined:—Blue L., Naree Budjong Djara Natl Park, North Stradbroke Is., Crystal Ck at Bypass Rd.

Other records:— New South Wales: Central Coast: McCarrs Ck, Ku-Ring-Gai Chase Natl Park, Entwisle, 2000 (NSW); Brisbane Waters Natl Park, Coveny, 2000 (NSW); Sydney International Rowing Course, Penrith Lakes, S. Skinner, 2000 (NSW); Gap Ck Falls, Olney S.F., Cherry, 2000 (NSW). Northern Territory: billabong 25 km SW of Bullita Outstation, Gregory Natl Park, C.A. Coles, 1996 (MEL 2277156A).

Observations:—Metaphytic or attached to submerged and emergent aquatic plants in the littoral zone of subtropical wallum lakes, acidic tropical streams and waterholes (Komárek 2013).

Figures

FIGURE 77. A–E Scytonema subtile; E Colonies periphytic on the culms of the emergent sedge Lepironia articulata. Scale bars = 20 μm