Coleodesmium sp. A

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

Coleodesmium sp. A . Fig. 90 A–C.

Thallus heteropolar, attached at one end to the substratum, forming tufted, shrub-like colonies up to 8 cm in diameter; richly branched, mostly with lateral tangential false-branching, initiated by the lateral formation of a heterocytes; branches remain joined parallel to the mother filament and diverging on the upper parts, 21–45 μm wide; sheath hyaline or yellow-brown in colour, smooth, thin and occasionally crimped, extending just beyond the apex of the filaments. Trichomes cylindrical, constricted at the cross walls. Heterocytes generally solitary, ovoid, spherical or elliptical, basal and intercalary. Vegetative cells always distinctly broader than long, 16–19 (–20) μm broad, apical cells broadly rounded and often vacuolate. Akinetes not observed.

Specimens observed:—Mossman R. at Mossman Gorge, Daintree Natl Park.

Observations:—Epilithic on boulders and large granitic rocks, in rapidly flowing water in the upper coastal tropical rainforest reaches of the Mossman R. These populations most closely resemble C. wrangelii Borzì ex Geitler (1942: 356) however, the filaments are much broader. C. wrangelii has been reported by Entwisle (1994) and Skinner & Entwisle (2001) from similar montane habitats from the Lamington Natl Park in Queensland to the Marysville and Whitehouse Ck areas of the Victorian highlands and the upper reaches of the Yarra Valley.

Other species known from Australia: C. wrangelii, Canungra Ck, Picnic Rock, Lamington Natl Park , Queensland, Entwisle , 1993 ( MEL) , Polblue Ck near Polblue camping area, Barrington Tops, New South Wales, Entwisle , 1999 ( NSW) , Chichester S.F., near Barrington Tops, New South Wales, Entwisle , 1991 ( MEL) , Chaelundi Ck at Chaelundi Rest Area , Guy Fawkes Natl Park, New South Wales, Skinner & Cherry, 2000 ( NSW) , Deer Park R., Waterfall Way, New South Wales, Skinner , 2000 ( NSW) , Bullock Ck, 2 km in from Hwy on Point Lookout Rd, New South Wales, Skinner , 2000 ( NSW) , seepage 500 m from summit of Mt Kosciuszko, New South Wales, Entwisle , 2000 ( NSW) , Merrits Ck Mt Kosciuszko Walk, New South Wales, Entwisle , 2000 ( NSW) , tributary of Thredbo R., Crackenback Ridge, Thredbo, New South Wales, Entwisle , 2000 ( NSW) , Geroa R, Rockton, New South Wales, Entwisle , 1991 ( MEL) , Mongarlowe R., 17 km SE of Braidwood, New South Wales, Entwisle , 1991 ( MEL) , Yowrie R. at Yowrie R. Crossing, New South Wales, Skinner , 2000 ( NSW) , Steavenson R., Marysville, Victoria, Entwisle , 1993 ( MEL) .

TOLYPOTHRIX

Tolypothrix Kützing ex Bornet & Flahault (1886: 118)

Type: T. distorta Kützing ex Bornet & Flahault (1886: 119)

Filaments heteropolar, united into fasciculate, caespitose colonies, or dense woolly mats, basal parts with heterocytes and free apical ends, commonly falsely branched, usually with solitary lateral branches; branches initiate at intercalary, unipored heterocytes, divergent from the main filaments or for a short distance joined to the main filament and later diverging. Sheaths thin or thick joined to the trichome, sometimes lamellated, colourless or yellow-brown in colour, open at the apex. Trichomes and branches uniseriate, with one or several basal heterocytes, cylindrical, not attenuated at the end, constricted or unconstricted at the cross walls. Vegetative cells cylindrical to barrel-shaped, isodiametric or slightly longer or shorter than wide, without aerotopes, blue-green, olive-green, greyish or reddish in colour, apical cells slightly narrowed or widened and rounded, sometimes spherical, without calyptra, sometimes vacuolated. Akinetes known from a few species. Cells divide crosswise to the trichome axis, with sub-terminal meristematic zones. Reproduction by hormogonia which separate at both ends.

A worldwide genus with species from aerophytic, marine and freshwater environments; 66 species are currently accepted taxonomically, six species are known from Australia, one species is described here from north-eastern Australia. Bibliography: Playfair (1971, 1918), Skinner & Entwisle (2001), Hauer et al. (2014).