Full name: Hebeloma moseri Singer (1969)
Published: Beihefte zur Nova Hedwigia 29: 287 (1969)
Taxonomic status: Heterotypic synonym of H. mesophaeum
Types: ARGENTINA: Neuquen, Quetrihue, Patagonia (approx. 38.9555°S, 68.0632°W, alt. approx. 270 m a.s.l.) on soil in woodland under Nothofagus dombeyi, 15 Apr. 1963, M. Moser (Holotype. herbarium acc. no. ZT 75-424, HJB1000116).

Original diagnosis: Pileo gilvo, subrubescente-brunneo discum versus, interdum subgriseo-brunneo et albido-marmorato, glabro et nudo, 10-40-(50) mm lato, obtuse conico vel semigloboso, irregularicer flexuoso. —Lamellis dilute cacao-coloribus, tridymis, lamellis integris 40, i.e. distantibus, crassiusculis, ad aciem haud strictis vel suberosis, adnatis. —Stipite dilute griseolo-brunneolo, basin versus fuligineo-brunneo, ad apicem subtiliter fibrilloso-squamuloso, aequali vel basin versus incrassato, 25-30 x (ad apicem) 2.5, (ad basin) 8-(10) mm. —Contexto raphanaceo odore gaudente. —Sporis 12-12.3 x 6.5—6.8 μ ellipsoideo-fusoideis vel ellipsoideis (e basidiis bisporis natis) vel 9-9.5 x 5.3-6 μ, ellipsoideis, sic e basidiis tetrasporis natis, depressione leniter manifesta suprahilari praeditis, ad apicem subacuminatis, praesertim in maximis, callo apicali ornatis, subtiliter punctulatis subasperulisque vel levibus, maximis omnibus levibus, ochraceis.—Hymenio e basidiis efformato et cheilocystidiis marginato. Basidiis 27-42 x 7.2-8.5 μ, clavatis vel medio constrictis, hyalinis, (1)-2-(3)-4-sporis, pluribus tetrasporis. Cheilocystidus 42-52 x 7.5-8.7 μ, ampullaceis, in parte inferiore ventricosis, sub apice claviculari 4.5-5.8 μ lato leniter constrictis et ibi 3-3.7 μ diam., hyalinis, numerosissimis et densis. —Hyphis fibulatis. —Ad terram in silva, sub Nothofago dombeyi, frequenter caespitose-fascicularis.

English translation: Pileus yellow, pale reddish-brown towards the disc, at times pale greyish-brown and mottled with white streaks, glabrous and naked, 10-40 (50) mm broad, obtusely conical or semiglobate, irregularly lobate. – Lamellae light cocoa-coloured, tridynamous (threesome), entire lamellae 40, i.e. distant, thickish, edge not at all entire or slightly eroded, adnate. – Stipe pale greyish-brownish, sooty-brown towards the base, slightly fibrillose-squamulose at the apex, equal or enlarged towards the base, 25-30 x (at the apex) 2.5, (at the base) 8 (-10) mm. – Context having a raphanoid smell. – Spores 12-12.3 x 6.5-6.8 μ, ellipsoid-fusoid or ellipsoid (from bisporic basidia) or 9-9.5 x 5.3-6 μ, ellipsoid, from tetrasporic basidia, with hardly visible suprahilar depression, at the subacute apex, especially in the largest ones, ornate with an apical callus, minutely punctate, almost roughened or smooth, the largest all smooth, ochraceous. – Hymenium constituted by basidia and cheilocystidia on the edge. Basidia 27-42 x 7.2-8.5 μ, clavate or constricted in the middle, hyaline, with (1)-2-(3)-4- spores, the majority tetrasporic. Cheilocystidia 42-52 x 7.5-8.7 μ, ampulliform, ventricose on the lower part, under a clavuliform apex 4.5-5.5 μ wide, slightly constricted and there 3-3.7 μ in diameter, hyaline, very numerous and dense. – Hyphae clamped. – On the ground in woods, under Nothofagus dombey, frequently caespitose-fasciculate.

Commentary: The term tridynamous (threesome) in the diagnosis means in groups of three. We take it that this should be interpreted as that between two entire lamellae there are three lamellulae, the one in the middle longer than the two on the sides. Based on molecular and morphological analysis this is: = Hebeloma mesophaeum (Pers.) Quél.