Cap 10-40 mm across, parabolical to conical or campanulate, becoming broadly convex to applanate, ±umbonate, ±sulcate, translucent-striate, dry, slightly lubricous when moist, very dark sepia brown to black or even bluish black at the centre, sepia brown farther outwards, fading to grey-brown with age, margin paler, white to brownish. Gills 16-24 reaching the stem, adnexed, sometimes decurrent with a short tooth, strongly veined or rugose and intervenose with age, white to dark grey, edge concolorous to paler. Stem 30-80 x 4-5 mm, stocky, cylindrical or somewhat compressed and fissured lengthwise, at first conspicuously white-puberulous all over, glabrescent for the greater part (except at the apex), slate-coloured, dark bluish grey, particularly at the apex, gradually becoming paler and turning somewhat more brownish, base densely covered with long, fairly coarse, somewhat woolly, white fibrils. Odour nitrous, taste not recorded. Basidia 25-35 x 6.5-8 µm, slenderly clavate, 2-spored, with sterigmata up to c. 8 µm long, or 30-45 x 8-9 µm, 4-spored. Spores (7.6-)9-11.8(-14) x (5-)6-7.2(-8.5) µm, Q = 1.6-2.3, Qav ˜ 1.8 (2-spored) or 7.6-9 x 5.4-5.6 µm, (4-spored), pip-shaped, amyloid. Cheilocystidia 20-60 x 7-16 µm, more or less forming a sterile band, clavate to fusiform, smooth, apically broadly rounded or mucronate, more rarely with a longer, slender neck. Pleurocystidia similar, scanty, unobtrusive. Lamellar trama dextrinoid. Hyphae of the pileipellis 2.5-6.5 µm wide, smooth. Hyphae of the cortical layer of the stem 1.5-4.5 µm wide, smooth, terminal cells (caulocystidia) 25-90 x 2-22.5 µm, cylindrical, narrowly to broadly clavate, ellipsoid to more or less irregularly shaped, simple or, more rarely, furcate, smooth. Clamps present in all tissues in 4-spored form, absent in 2-spored form.
Ecology and distribution
Gregarious to cespitose in grass or on needles near Juniperus. Autumn. Not yet known outside the type locality in SE Norway, where it has been collected on three different places.