In basidium length, Platygloea australis resembles P. sebacea (Berk. & Br.) McNabb, but differs in the size and shape of spores, larger and darker coloured fructifications, and absence of a stipe cell at the base of the basidium. A number of Platygloea species are fungicolous and although the fructifications of P. australis were adjacent to Diatrype perithecia, no evidence of parasitism could be found.

On dead Pittosporum sp., Auckland, Henderson Valley, Sharp's Bush, 20.ii.l966, R. F. R. McNabb (HOLOTYPE, PDD25293).

Fructifications firm-gelatinous, determinate, erumpent through the bark, pustulate at first, becoming bluntly lobate to gyrose, forming areas to 5.5 cm long, to 7 mm high, dull brown when fresh, drying blackish brown, vernicose or horny film. Internal hyphae thin-walled, 4-5.5 µm, diam., both simple septa and conspicuous clamp connections present. Hymenium composed of basidia, dikaryophyses absent; basidia borne singly or in terminal groups by proliferation through basal clamp connections, narrowly subclavate, transversely 3-septate, 180-295 x 5-6.5 µm, sterigmata cylindrical, to 77 x 3 µm. Basidiospores cylindrical to curved-cylindrical, occasionally allantoid, hyaline, bluntly apiculate, 15.4-23.8 x 6-7.8 µm. Germination not observed.

Dead angiosperm wood.

Fructificationes firmiter gelatinosae, obtuse labatae ad gyrosas, ad 5.5 cm longae, ad 7 mm altae, sordide brunneae; hyphae internae 4-5.5 µm diam., nodosae. Dikaryophyses absunt; basidia anguste subclavata, 3-septata, 180-295 x 5-6.5 µm; sterigmata cylindrica, ad 77 x 3 µm. Basidiosporae cylindricae ad curvo-cylindricas, interdum allantoides, 15.4-23.8 x 6-7.8 µm. Habitat in mortuo Pittosporo.

Typus Auckland Province, Henderson Valley, Sharp's Bush, 20.II.l966, R. F. R. McNabb, PDD25293.