Full name: Hebeloma cinereum Velen. (1920)
Published: Ceske Houby: 396 (1919) ["1920"]
Taxonomic status: Heterotypic synonym of H. mesophaeum
Types: CZECH REPUBLIC: Sarka, Prague (approx. 50.09°N, 14.41°E, alt. approx. 240 m a.s.l.), Oct. 1919, J. Velenovsky (Lectotype. herbarium acc. no. PRC B105, HJB1000240). Lectotype designated by Beker et al., Hebeloma (Fr.) P. Kumm.: (2016) page 579 (MBT201356).

The lectotype was collected in 1919 so is almost certainly part of the original material.

Original diagnosis: Parvum, habitu Inocybas parvas in mentem revocans. Pileus 2-3 cm diam., tenuiter carnoso, explanato, obtuse umbonato, levi, udo subviscido, ahygrophano, plumbeo-griseo, vertice nigro-fusco. Stipe longo, recto, ca 3 mm crasso, basi non incrassato, rigido, albo-fibilloso, apice a velo debiliter furfuraceo-anulato, supra hoc albo-fibrilloso, apex de velo debiliter furfuraceo-anulato, supra hoc albo-granuloso, iuventute cortina sat debili cum pileo coniuncto, basi pallide subfusco. Lamellis confertis, decumbentibus, griseo-argillaceis, postice rotundato-liberis, acie albis. Spores ellipsoideis, basi oblique contractis, subhyalinis, 8-10 μ. Cystidiis acie numerosis, obtuse cylindraceis. Sine aromate. In valle Sarka Pragae octobri 1919 domina Fric legit. Solitarium. Pileo non hygrophano et conspecte colorate species insignis.

English translation: Small, reminiscent of a small species of Inocybe. Pileus 2–3 cm broad, thinfleshed, expanded, bluntly umbonate, smooth, subviscid when moist, not hygrophanous, leadgrey, blackish brown at centre. Stipe long, straight, about 3 mm thick, not broadened at base, rigid, white fibrous, with veil remnants in form of a floccose annuliform zone, white granulose at apex, when young with poorly developed cortina connected to pileus, pale brown at base. Lamellae crowded, decumbent, greyish clay-coloured, rounded-free, with white edge. Spores ellipsoid with blunt base, subhyaline, 8–10 μm. Cystidia along edge abundant, bluntly cylindrical. Odour absent. In the Sarka valley near Prague, October 1919 found by Mrs. Fric. Solitary. Distinct species with conspicuous colours, not hygrophanous.

Commentary: The ‘original diagnosis’ above is the translation into Latin from the original Czech by Pilat, Opera Bot. Čechica 6: 137 (1948). Judging from studies of the protologue and the lectotype, H. cinereum is: = Hebeloma mesophaeum (Pers.) Quél.