Cortinarius denigratus – Facesoffungi number: FoF 02039

Cortinarius denigratus Ammirati, Beug, Niskanen, Liimat. & O. Ceska

Index Fungorum number: IF 551703 Facesoffungi number: FoF 02039

Etymology: Name based on blackening of the basidiocarps on drying.

Holotype: Michael Beug 02MWB043014 (WTU) Pileus 10–20 mm diam., papillate umbo, dry, Dresden Brown to Mars Yellow, edge blackens dried (insun), minutely fibrillose, hygrophanous. Lamellae adnexed, ± distant, tan rusty. Stipe 30–40 mm long, 2–4 mm thick, ± equal, minutely fibrillose, buckthorn brown. Universal veil not recorded. Basal mycelium white. Context in stipe context ochraceous buff to yellowish tan. Odour indistinct. Macrochemical reaction (40 % KOH): all parts instantly black. Exsiccatae: pileus brown to blackish, lamellae dark dullbrown to blackish, stipe brown to blackish, some white mycelium at base, context brown. Basidia 4-spored, 9–10×27–37μm, clavate, hyaline, light brown or dark brown in KOH. Basidiospores 9– 11.2×4.8–6μm (20 spores, holotype specimens), narrowly to broadly amygdaloid, distinct apiculus, moderately to very coarsely verrucose, apex±extended and less ornamented, slightly to somewhat moderately dextrinoid. Lamella trama hyphae hyaline, light brown or very dark brown, walls yellow refractive, heavily brown encrusted and with brown inter hyphal plaques in KOH. Pileipellis in KOH: Surface layer thin, somewhat compressed, hyphae±cylindrical, 4–12μm wide, hyaline or yellowish, some encrusted. Subtending layer of cylindrical to enlarged hyphae 7–25μm wide, yellow brown to orange brown, walls yellow refractive, some heavily encrusted with brown pigment. Beneath a darker brown pigmented layer of encrusted hyphae with inter hyphal brown plaques, cylindrical to enlarged, mostly 7–22μm wide, that gradually grade into trama hyphae. ITS sequence distinct from other species of Cortinarius subgenus Telamonia.

Ecology and distribution: Found from forests of Quercus garryana and Pinus ponderosa, and Pseudotsuga menziesii and Arbutus menziesii. Producing basidiomata in spring in April. Known from British Columbia, Canada and Washington USA, Western North America.

Material examined: CANADA, British Columbia, Salt Spring Island, Mt. Tuam,48.72°N123.485°W, a long the trail through mixed forest (Pseudotsuga, Arbutus), 19 April 2007, leg. Oluna Ceska OC155,F17227 (UBC). USA, Washington, Klickitat County, Beug Farm, N45°48′36.6″ W121°30′ 59.04″, Quercus garryana and Pinus ponderosa, 30 April 2014, leg. Michael Beug 02MWB043014 (holotype, WTU), (isotype, K(M): 200659).

Notes: Cortinarius denigratus is easily recognized since it produces fruitbodies in the spring when not that many other Cortinarius species are fruiting. Characteristic for the species are small, brown basidiomata, highly brown pigmented lamella trama hyphae, and amygdaloid, rather large spores with±extended apex. Cortinarius denigratus is not very closely related to any of the known Telamonia species, but groups together with other small Telamonias in our phylogenetic analysis.