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Page number:119 
Description type:Non-original description 
Description:Pleurotus australis (Cke et Mass.) Sacc. Syll. Fung. 9 (1891) 46.
Agaricus australis Cke et Mass., Grevillea 15 (1887) 93; Cooke, Handb. Australian Fungi (1892) 37, p1.2 f. 10; Pegler, Austral. J. Bot. 13 (1965) 325.
Pileus -8 cm in radius, excentric to almost lateral, spathulate to flabelliform, varying subcircular and subgibbous, subsquamulose in the centre with small scurfy particles, or fibrilloso-scurfy from the break-up of the superficial tissue, fuscous brownish, paler and yellowish-drab towards the smooth substriate margin incurved at first. Stem 1.2-5 cm x 6-14 mm below, 10-25 mm above, excentric to lateral, attenuate to the abrupt base, finely fuscous scurfy pruinose, white villous downwards, fuscous, the apex shallowly reticulate from the decurrent gills. Gills decurrent, subdistant, broad, 22-32 or 40-SS primaries 9-15 mm wide, 4-6 ranks, white to pallid bistre, the entire edge white or fuscous brown near the stem-apex, often shallowly reticulate at the base. Flesh 10-20 mm thick in the centre of the pileus, 2-3 mm at half-way to the margin, firm, white. Smell strong, farinaceous (Sumatran collection) or none (Bornean collection).
On dead fallen trunks in montane forest, often imbricate and caespitose. Borneo, Sumatra, South Australia.
Spores 10.5-14.5 (-17) x 4-5 µm (RSNB 8059), 11-18 x 3.8-5 µm (Sumatran collection), white in the mass, smooth, cylindric, obtuse, thin-walled, inamyloid. Basidia 40-60 x 6-8 µm elongate-clavate; sterigmata 4, 5-6 µm long. Cheilocystidia -48 x 5-9 µm clavate to subventricose, often mucronate with a sterigma-like appendage subcapitate or not, thin-walled, smooth, forming a narrow sterile edge to the gill, with brownish cytoplasm near the stem-apex (RSNB 8059). Pleurocystidia 70-100 x 6-8 µm as long sterile basidia formed early in the developing hymenium and becoming imrnersed and scattered in the thick subhymenium, the wall slightly thickened -0.5 µm in the proximal part, some with tapered apex as an appendage -18 x 2-3 µm colourless, smooth, not gloeocystidial; easily overlooked. Hymenium not thickening; subhymenium 15-30 µm thick.
Hyphae monomitic, clamped, inflating, 2-15 (-22) µm wide, the cells 25-160 (-200) µm long, becoming slightly thick-walled in the stem, branching at a wide angles no skeletal cells in the hyphae.
Gill-trama with descending hyphae, becoming interwoven. Surface of pileus with appressed hyphae 2-8 gm wide, the outermost with slightly thickened brownish walls and thin brown incrustation, some with oily brownish cytoplasm, the cells 20-70 µm long; over the centre of the pileus with many obliquely excrescent hyphae -150 µm long, the end-cells cylindric or subclavate 4-10 µm. wide. Surface of stem with a pile of narrow hyphae up to 900 µm high but shorter towards the stem-apex and passing into the Cheilocystidia, the hyphae 1.5-3 µm wide, septate, with thin or firm colourless smooth walls, set at right angles to the narrow longitudinal hyphae on the surface of the stem, mostly unbranched, often subfasciculate; the pile of hyphae derived from a loose layer c. 200 gm thick of longitudinal hyphae 3-5 µm wide, with brownish cytoplasm.
Collections: Sumatra, Brastagi, 2000 m alt., Comer s.n. 15 Sept. 1931. - Borneo, mt. Kinabalu, Mesilau, 1600 m alt., RSNB 8059, 2 April 1964.
This description is based on the Malaysian collections. It suggests Pl. ostreatus but it has longer spores white in the mass. It also has pleurocystidia, formed as the first and sterile basidia in the developing hymenium. These collections agree with the meagre description, but characteristic illustration, given by Cooke and Massee. Pegler has confirmed that the spores of the type, from Australia, are 9.5-14 x 3.2-5 µm, not 16-18 x 4 µm though spores as large were produced by the Bornean collection. Thus, it is, that one has to be cautious on spore-size. The Australian fungus grew on roots of Leptospermum.
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