Types: FRANCE: Foret de Hez,Le Val Hemont, nr Hermes(Oise) (approx. 47.74°N, 2.54°W, alt. approx. 55 m a.s.l.) on calcareous, mossy soil in mixed woodland under Betula verrucosa, Pinus sylvestris and Salix sp., 1 May 1970, H. Romagnesi (R70-34) (Holotype. herbarium acc. no. PC 0022088, HJB1000032).

Original diagnosis: Pileo 2-4 cm, convexo, mox truncato, deinde plano-convexo, primum medio obtuso vel paulum umbilicato, serius magis minusve mammoso, margine primum curva, juventute e rufulo ochraceo, dein pallidiore, ad istar Cortinarii hinnulei, in ambitu argenteo canescente, cute subtiliter fibrillosa, parum viscidula. Stipite 30-60 x 3-8 mm, cylindrato, farcto, sursum primum albo, e basi fuscescente, leviter sub lamellis pruinoso, alibi fibrilloso. Cortina alba, copiosa. Carne albida, in stipite fuscescente; odore herbaceo, paulum raphanoideo; sapore raphanoideo, dein lente amariusculo. Lamellis subdistantibus, 4-8 mm latis, segmentiformibus vel semiventricosus, maxime sinuatis, primum pallide brunneolis, dein ex argilleis brunneis, aciepruinosa ac albida. Sporis 9-13 x 5-5,7 [5.7–7] μm, ellipsoideis, sub micr. stramineis vel pallide luteolis, sublevibus. Pilis marginalibus magis minusve lageniformibus, inferne ampullaceis, 30-60 x 8,5-11,5 μm (ad apicem 4-6,5 μm). Epicute gelata, hyphis filiformibus (x 2-4,2 μm), sub cute pigmento membranari vivide colorata, specie parum manifeste seudoparenchymatica. - Inter muscos (Abietinellum abietinam et Camptothecium lutescens), in prato calcareo, prope paucas Pinus silvestres et Betulas verrucosas, primo vere.

English translation: Pileus 2–4 cm, convex, soon truncate, then plano-convex, at first blunt or weakly umbonate at centre, later broadly umbonate, with margin incurved when young, when young reddish ochre, then fading, much resembling Cortinarius hinnuleus, entirely silvery greyish (by veil remnants); surface delicately fibrillose, not very viscid. Stipe 30–60 × 3–8 mm, cylindrical, stuffed, at first white at apex, at base turning reddish brown, slightly pruinose under the lamellae; white fibrillose. Cortina white, abundant. Context white, in stipe becoming reddish brown; odour herbaceous, weakly raphanoid; taste raphanoid then slightly bitter. Lamellae subdistant, 4–8 mm broad, segmentiform to semi-ventricose, with sinuate edge; pale brownish at first then clay-brown with white, pruinose edge. Spores 9–13 × 5–5.7 [5.7–7] μm, ellipsoid, under microscope straw-yellow to pale yellow, almost smooth. Marginal hairs large, more or less lageniform, swollen at base, 30–60 × 8.5–11.5 μm (at apex 4–6.5 μm). Epicutis gelatinous, made up of filiform hyphae (× 2–4.2 μm); subcutis with vividly coloured membranous pigment, not very manifestly parenchymatous. Among mosses (Abietinella abietia and Camptothecium lutescens) in calcareous meadow, with some Pinus sylvestris and Betula verrucosa in the vicinity; early spring.

Commentary: Based on morphological analysis together with ITS sequence data, this is: = Hebeloma dunense L. Corb. & R. Heim.