Cleistocybe

Cleistocybe Ammirati, A.D. Parker & Matheny 2007, in Ammirati, et al., Mycoscience, 48, 282-289 (2007)

Etymology: Cleistos (Greek: closed, shut) and -cybe(Greek: head) in reference to the veiled basidiomata.

Diagnosis: Habit clitocyboid, veil present or ephemeral, thin to fibrillose or membranous and leaving a more or less distinct annulus, pileus convex to plane becoming depressed, margin enrolled to incurved or decurved, surface non-viscid or viscid, appressed fibrillose to squamulose or with agglutinated fibrils, nonhygrophanous, margin opaque, color brick red to light reddish brown with margin light pinkish cinnamon, buff, or paler, or with vinaceous brown fibrils over a pinkish-gray ground color; context of pileus thick but tapered abruptly to margin, confluent with stipe context, solid in stipe, pale pinkish gray to pale vinaceous buff; odor and taste strongly farinaceous; lamellae decurrent to long decurrent, close, crowded or subdistant to distant, relatively narrow, sometimes forked, light pinkish brown, pale pinkish gray to light gray, darkening in age to grayish or brown gray; stipe central, equal to clavate or tapered slightly downward, surface dry, appressed fi brillose to squamulose below, base cottony, color pale pinkish gray, pale vinaceous gray to vinaceous buff. Basidiospores white in deposit, in face view usually elliptical to elliptical oblong, in profile view elliptical to ovate or subfusoid to subcylindrical, often strongly inequilateral, smooth, distinctly apiculate, inamyloid, not cyanophilous, relatively thin-walled. Basidia narrowly clavate to clavate, sterigmata prominent, usually 4-spored but sometimes 1–3-spored, typically colorless or with granular contents; hymenophoral cystidia absent; pileipellis interwoven, nongelatinous or gelatinous in 3% KOH, hyphae cylindrical, narrow, often flexuous, sometimes encrusted, colorless, yellowish, orange or orange-brown; pileal trama interwoven, hyphae cylindrical or less commonly broadly cylindrical, colorless to yellowish, some encrusted, thin-walled or slightly thickened, walls refractive; lamella trama interwoven to subparallel but more or less divergent when young, hyphae cylindrical, with a tendency to undulate, colorless; veil hyphae similar to those of pileipellis, cylindrical, parallel to interwoven, colorless to yellowish and refractive; oleiferous hyphae present; clamp connections present. Terrestrial, solitary to caespitose, or in clusters on soil under mixed conifers (Abies, Larix, Pseudotsuga, Thuja) or conifers mixed with Betulaceae (Alnus, Betula).