Pileus up to 19 x 8 mm when still closed, 18--25(--30) mm when expanded, cylindric-ellipsoid at first, later campanulate, finally applanate or even revolute at deliquescence, greyish white at first, with a grey or grey-brown disc, covered with hairy fibrillose, greyish veil, brownish to sepia at the centre, split up toward the periphery in small upturned browning scales. Lamellae (number not noted) fully deliquescent, ascending, free, narrow, very crowded, 2--5 mm high, white at first, then grey and finally blackish, with a lighter, whitish but turning to pink, scurfy edge. Stipe 40--80 x 1--3 mm, white, up to 4 mm at the base, slightly tapering towards the apex, at base clavate or slightly bulbous, hollow, vaguely flocculose, more densely towards base.
  Spores [80,5,3] 8.8--12.7(--13.1) x 5.7--8.3 mm; Q = 1.30--1.75; av. Q = 1.40--1.60; av. L = 10.1--11.6, av. B = 6.5--7.6 mm, ovoid or ellipsoid with slightly conical or (less frequent) rounded base and rounded or somewhat truncate apex, dark red-brown, and central or slightly eccentric, 1.5--1.8 mm wide germ pore. Basidia 24--34 x 6--9 mm, 4-spored, surrounded by 3--5 pseudoparaphyses. Pleurocystidia 60--90 x 24--35 mm, oblong, subcylindric or utriform. Cheilocystidia 30--50 x 18--25 mm, (sub)globose, ovoid, ellipsoid, oblong, utriform or subcylindric. Pileipellis a cutis, made up of cylindrical, more or less parallel, repent hyphae. Veil made up of elongate elements in chains, cylindric or somewhat inflated, often constricted at septum, 20--180 x 6--40 mm, with fusiform, ellipsoid, oblong, ovoid or cylindrical terminal elements, slightly but distinctly thick-walled, walls up to 1 mm thick. Clamp-connections present.

Habitat & distribution

  Solitary, fasciculate or gregarious on rotting wood chips. Very rare. Only known from the type locality (State of Washington, USA) and one find from Europe (England).