[GS] Pileus 2-5-4.5 cm - diam., black, velvety fibrillose, more or less plane becoming irregularly waved, margin down-rolled. Gills adnate, grey, thick, shallow, moderately crowded. Stipe 2-3 cm. x 3-6 mm., centric to excentric, greyish sepia, fibrillose to fibrillose-scaly with or without tufts of fibrils at base. Spores 5-6 X 2.5-3um, amyloid (Fig. 2/5, p . 37). Cuticle of closely woven almost parallel hyphae with dark to very dark walls. HABITAT: on fallen wood, Ohau River, 25.5.1952, Stevenson (type). This species is close to but distinct from the Australian Pleurotus sulciceps Cooke & Massee, the type-specimen of which has been examined. [EH] = Hydropus sp. Spores oval to elliptical, hyaline, weakly amyloid, smooth, 4-4.5 X 2-2.5 um. Cystidia none. Cuticle with intermixed oleiferous hyphae showing in KOH a dark brown plasmatic pigment, with clamp connections. [JAC] The fragments appear suspiciously black, as if dried poorly, or at excessive heat (like some Stevenson Mycena collections), or intrinsically blackening (Lyophyllum/Tephrocybe). Some caps show a brown colouration and I am not convinced by the original descriptions as black, and neither is the cap surface velvety fibrillose and the stem also not scaly. 4-spored. Basidia with pale brown plasmatic content in KOH and micro-crystals on hymenial tissue. Lamellae with rare patches of cylindrical basidiolar cheilocystidia. The spores do not appear to be amyloid. Spores on cap have a brownish colouration, and perhaps not from the frb. Pileipellis an irregular trichoderm of long hyaline hairs. The subpellis irregular with hyaline and brown oleiferous inflated hyphae and occasional hydropid-looking brown vesicles. Spores (from gill not cap), excluding apiculus length=4.8–5.9µm (µ=5.3, σ=0.37), width=2.1–2.9µm (µ=2.6, σ=0.19), Q=1.8–2.2µm (µ=2.02, σ=0.12), n=14. This appears to be porothelioid rather than related to Pleurella ardesiaca. It does not conform to any of the taxa currently known by me.

[Notes from Kew Type specimen, PRJ 2010] Kew images.

Pileus 2.5-4.5 cm diam., black, velvety fibrillose, more or less plane becoming irregularly waved, margin down-rolled. Gills adnate, grey, thick, shallow, moderately crowded. Stipe 2-3 cm x 3-6 mm, centric to excentric, greyish sepia, fibrillose to fibrillose-scaly with or without tufts of fibrils at base. Spores 5-6 x 2.5-3 µm, amyloid (Fig. 2/5, p. 37). Cuticle of closely woven almost parallel hyphae with dark to very dark walls.

On fallen wood, Ohau River, 25.5.1952, Stevenson (type),

Pileus 2-5-4.5 cm diam., niger, velutino-fibrillosus, plus minus planus, deinde irregulariter undulatus, margine deorsum involutus. Lamellae adnatae, griseae, crassae, haud altae, modice confertae. Stipes 2-3 cm x 3-6 mm, centricus usque excentricus, griseo-sepiicolor, fibrillosus usque fibrilloso-squamosus, basi nonnunquam cum fasciculis fibrillorum. Sporae 5-6 x 2.5-3 µm, amyloideae. Cuticula ex hyphis dense intertextis plus minus parallelis, parietibus fuscis usque valde fuscis.

This species is close to but distinct from the Australian Pleurotus sulciceps Cooke & Massee, the type specimen of which has been examined.

Typus: Stevenson 842.