Cortinarius colymbadinus

Pileus 20–70 mm, hemispherical, then low convex to almost plane, with a low umbo, diffracted towards margin, finely fibrillose when young, hygrophanous, chocolate brown to olivaceous yellow brown, with a characteristic, metallic, olivaceous yellow shine, which persists on drying.
Lamellae medium spaced, emarginate, yellow-brown to cinnamon brown when young, later darker, with yellow, often uneven edge.
Stipe 40–100 mm long, 4–10 mm thick at apex, cylindrical to somewhat clavate, silky-fibrillose, slightly glossy, greyish yellow to brown, towards base dark brown, base with yellow mycelial felt, cortina sparse. Universal veil greenish yellow, sparse, initially sock-like, then forming a thin ring-like or indistinct zone.
Context in pileus thin, pale brownish, in stipe often hollow, with hygrophanous streaks, brown, darker towards base.
Basal mycelium greenish yellow.
Odour indistinct or slightly raphanoid.
Exsiccata pileus dark brown, dark yellowish brown to very dark brown, becoming very dark greyish brown to black towards centre. Stipe olive brown, base of stipe (basal mycelium?) yellow.
UV observations: positive almost on the whole basidiomata, especially the stipe and the edge of the lamellae (chrome yellow), cap paler yellowish.
Spores: 7.5–9.5×4.5–5.5 μm, Q=(1.5)1.6–1.8(1.9), av. 8.1–8.7×4.8–5.3 μm, Q(av.)=1.63–1.79, amygdaloid, strongly to very strongly verrucose, moderately to fairly strongly dextrinoid.
Basidia 4-spored, 22–31×7–9 μm, clavate, olivaceous yellow in MLZ. Lamellar edge fertile, with numerous, clavate sterile cells, concolorous with the basidia.
Lamellar trama hyphae olivaceous yellow in MLZ, finely encrusted (rarely with spot-like incrustation).
Pileipellis duplex, in overall view pale yellowish brown, epicutis thin to moderately thick, hyphae 3–8 μm wide, hyaline or with yellowish brown content, slightly encrusted or smooth. Hypoderm weakly developed, elements 10–22 μm wide, hyaline, smooth. Clamp connections present.
ITS-regions (including 5.8S region): Maximum pairwise distance of the sequences is 0 (includes two polymorphic sites). Cortinarius colymbadinus differs from C. uraceomajalis by 13 substitutions and indel positions and from C. nolaneiformis by 21 substitutions and indel positions.
Ecology and distribution: In mesic Picea forests,mostly on rich soil. Producing basidiomes from summer to autumn, often fruiting early in the season. Widely distributed and occasional in Europe. Sequenced collections are from northern Europe (Finland and Sweden) and central Europe (Austria, Hungary).