Nostochopsis lobatus H.C.Wood ex Bornet & Flahault (1886: 80)

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

Nostochopsis lobatus H.C.Wood ex Bornet & Flahault (1886: 80) Figs. 33 A–D, 34 A–B .

Thallus spherical, sub-spherical or irregularly lobed, either solid throughout or hollow, 3–30 cm in diameter, blue-green to yellow-brown in colour; mucilage homogeneous, colourless or yellow-brown, diffluent at the ends. Filaments cylindrical, radially arranged, laterally branched, often slightly widened and club-shaped at the ends. Vegetative cells of the main axis 5.5–8.0 μm long × 3.5–5.5 μm broad; lateral branches generally smaller, 5–7 μm long × 2–3 μm broad. Heterocytes spherical or sub-spherical, 6.0–7.5 μm long × 5.5–7.0 μm broad, attached to the main axis or laterally on the ends of short 1–3 celled branches.

Specimens examined:—Mary R. at Gympie, Reedy Ck at Mount Byron Rd, South Pine R. at Carter Court, Christmas Ck at Stinson Memorial Park.

Other records:— Queensland: Reynolds Ck, A.B. Cribb, 1949 (BRI 0701824), Burham R. at Sapling Pocket,A.B. Cribb, 1981 (BRI 0701825), Upper Millstream Falls, A.B. Cribb, 1973 (BRI 0701827), Mt Crosby Weir on spillway, A.B. Cribb, 1971 (BRI 0701828), Canarvon Gorge, A.B. Cribb, 1969 (BRI 0701829), Obi Obi Ck, A.B. Cribb, 1969 (BRI 0701831), Carney’s Ck, A.B. Cribb, 1963 (BRI 0701833), Gap Ck, Cunningham’s Gap, A.B. Cribb, 1964 (BRI 0701835), Cedar Ck Falls, Conway Natl Park, Proserpine, Entwistle, 1993 (MEL), Murray Falls, Cardwell, Entwisle, 1993 (MEL), Millstream Falls, A.B. Cribb, 1973 (BRI 0701827), SE Queensland, McLeod (1975); New South Wales: MacDonald R., Walcha Rd, Entwisle, 1970 (NSW).

Observations:—Originally described from temperature streams in north-eastern United States. Recorded in Australia from central northern New South, through to north-eastern Queensland, but is probably more widespread. Observed here growing on granitic rocks in some small shallow coastal streams amongst colonies of Nostoc .

4. NOSTOCACEAE

Nostocaceae Agardh ex Kirchner (1898: 101)

Type: Nostoc Vaucher ex Bornet & Flahault (1886: 181)

Filamentous, heterocystous, isopolar, with free localised uniseriate trichomes enveloped by fine or firm mucilaginous envelopes or sheaths. Filaments ± straight, flexuous, or ± irregularly screw-like coiled, without branching. Trichomes isopolar, cylindrical or moniliform, constricted or unconstricted at the cross walls, sometimes narrowed towards the apices, usually without meristematic zones, all vegetative cells capable of cell division. Vegetative cells spherical, barrel-shaped to cylindrical, apical cells rounded, conical, acutely pointed or cylindrical and bluntly rounded. Heterocytes terminally on both ends, or intercalary. Akinetes often several times larger than vegetative cells, formed from one vegetative cell or from the fusion of several vegetative cells, positioned adjacent or remote from heterocytes. Reproduction by formation of hormogonia, or by akinete germination.

A cosmopolitan family of 18 genera, including more than 400 species; seven genera are described here from north-eastern Australia, mostly from benthic or metaphytic habitats.

Figures

FIGURE 34. A–B Colonies of Nostochopsis lobatus growing on granitic rocks.