Pseudoclitocybe (Singer) Singer, in Mycologia 48(5): 725 (1956)
Diagnosis: Pileus 2–12 cm, depressed to umbilicate, hygrophanous, striate or not, slightly gelatinized, smooth to pruinose at margin. Lamellae: adnate to deeply decurrent, crowded, thin, whitish to gray. Stipe 4.5–8 x 1.3–2.2 cm, fistulose, cylindrical to compressed at maturity, concolorous with the pileus, usually with a white zone at apex; mycelium usually abundant, patch-like, without rhizomorphs. Context whitish to grey when moist. Smell herbaceous. Basidiospores globose to ellipsoid, smooth, distinctly amyloid, acyanophilic, with hyaline content. Basidia 4-spored, without carminophilic/siderophilous granulation. Cystidia absent. Subhymenium branching, prostrate, easily dissociated. Hymenophoral trama subregular to slightly divergent, cylindrical hyphae with elements 4–6 µm wide. Pileipellis a radially arranged ixocutis, sparsely to densely diverticulate. Clamp connections loop-like, present in mycelium in all species, absent or very rare elsewhere, absent at the base of basidia. Saprobe, terricolous, lignicolous to coprophilous. Temperate areas, Northern and Southern Hemispheres.
Index Fungorum number: IF18385
Type species: Pseudoclitocybe cyathiformis (Bull.) Singer, Mycologia 48(5): 725 (1956)
Notes: At least four distinct genetic lineages were found within genus Pseudoclitocybe in the ITS rDNA analysis: one of them found in Europe, North America and Asia (Pseudoclitocybe cyathiformis), one known only from Europe (Pseudoclitocybe obbata), another one found in North America (KF291250 and LIP 0401355, maybe Pseudoclitocybe oregonensis (Murrill) Singer?), and last a single sequence coming from New Zealand (HQ533021). Two cryptic lineages within P. cyathiformis were sometimes significantly supported, although frequently merged together in the analyses because of the presence of apparently intermediate sequences (KP453709, KR673477).
The intracellular globules characteristic of most Pseudoclitocybaceae are only frequent in the stipititrama of Pseudoclitocybe, and clamp connections have only been detected on mycelial hyphae (except for a few on stipitipellis of P. cyathiformis Lineage II). Subpellis is hardly differentiated in P. cyathiformis Lineage II, perceptible in P. cyathiformis Lineage I, and absent in P. obbata. The development of the hymenopodium (always with slender, anastomosing hyphae with divergent structure) follows the same pattern. Mediostratum is rather regular excepting in P. obbata where it looks more entangled. Suprapellis structures are rather specific, an ixotrichocutis with few, unbranched erected elements in P. cyathiformis Lineage I, or rich in terminations either simple and cylindro-clavate (P. obbata) or versiform (P. cyathiformis Lineage II). Incrusting pigment is abundant in P. obbata and present in P. cyathiformis Lineage I, nearly absent in P. cyathiformis Lineage II. All species have parietal pigmentation in pileipellis and/or subpellis, and a yellow intracellular pigment in some hyphae of pileipellis. Vascular (thromboplerous) hyphae with deep yellow–brown content has been seen only in P. obbata, mostly in the hypophyllum region.
Pseudoclitocybe atra (Velen.) Harmaja 1974
Pseudoclitocybe bacillaris (Pers.) Singer 1961
Pseudoclitocybe beschidica Singer & Kuthan 1980
Pseudoclitocybe cyathiformis (Bull.) Singer 1956
Pseudoclitocybe expallens (Pers.) M.M. Moser 1967
Pseudoclitocybe foetida (G. Stev.) J.A. Cooper 2014
Pseudoclitocybe indica Rawla & S. Arya 1990
Pseudoclitocybe lapalmaensis Dähncke & Contu 2010
Pseudoclitocybe lenta Corner 1994
Pseudoclitocybe martipanis Singer 1969
Pseudoclitocybe obbata (Fr.) Singer 1962
Pseudoclitocybe obbata f. minor Bon & Lefebvre 1999
Pseudoclitocybe parvula Raithelh. 1974
Pseudoclitocybe sabulophila (H.E. Bigelow) Contu 2010
Pseudoclitocybe sphagneti Raithelh. 1972
Pseudoclitocybe trivialis Raithelh. 1980