Dermoloma hygrophorus Joss.

Adamčíková, Katarína, Kiran, Munazza, Caboň, Miroslav, Matheny, Brandon P., Sánchez-García, Marisol, Arnolds, Eef, Caboňová, Michaela, Corriol, Gilles, Dima, Bálint, Friebes, Gernot, Griffith, Gareth W., Grootmyers, Django, Harries, David, Karich, Alexander, Mešić, Armin, Mihaljevič, Martin, Moreau, Pierre-Arthur, Pošta, Ana, Shapkin, Vasilii, Tkalčec, Zdenko, Vizzini, Alfredo, Vondrovicová, Lenka, Adamčík, Slavomir & Jančovičová, Soňa, 2025, A phylogenetic and morphological study of the genus Dermoloma (Agaricales, Tricholomataceae) in Europe and North America exposes inefficiency of opportunistic species descriptions, IMA Fungus 16, pp. e 157337-e 157337 : e157337-

Dermoloma hygrophorus Joss. , Bull. mens. Soc. Linn. Lyon 39 (1): 6. 1970.

Figs 31 c , 33

Holotype.

France • Ain, Quincieu , 5 Aug 1953, G. Lacombe and M. Josserand ( G 00127362 ).

Distinguishing characters.

European species; basidiomata large and robust, pale grayish, cream or almost white colors at all parts; pilei 25–45 mm in diameter; stipes 5–10 mm wide; lamellae up to 30 near the stipe attachment; spores amyloid.

Pileus 25–45 mm; convex to plane, sometimes indistinctly umbonate, sometimes asymmetrical; margin straight, sometimes lobate, not striate; surface matt, fairly smooth to rugulose-subsquamulose, slightly hygrophanous; colors start to fade from center, pale grayish cream, becoming white when drying. Stipe 30–40 × 5–10 mm; fusiform or cylindrical, usually narrowed towards the base, flexuous; surface glabrous to finely longitudinally striate, sometimes weakly pruinose or squamulose; color marbled with white and pale gray. Lamellae L = 16–30, l = (0 –) 1–3 (– 7), occasionally forked to strongly interveined-anastomosed; 4–8 mm wide; adnate-emarginate; color white to very pale grayish; edges entire or slightly irregular. Context up to 3.5 mm wide at mid-radius, 8 mm wide at center; fragile; odor strongly farinaceous.

Spores (4.8 –) 5.2–5.7 – 6.2 (– 7.1) × (3.6 –) 3.9–4.2 – 4.6 (– 5) μm; broadly ellipsoid to ellipsoid, Q = (1.08 –) 1.27–1.34 – 1.41 (– 1.53); walls amyloid; hilar appendage ca. 0.5–1 μm long. Basidia (20 –) 23–26.4 – 29 (– 32) × (4.5 –) 5.8–6.5 – 7.2 (– 8) μm; clavate; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 3–6 μm wide. Marginal cells not observed. Pileipellis ca. 30–40 μm deep; suprapellis mainly of one or two layers of inflated, irregularly arranged cells; subpellis not well-differentiated, of densely packed, mainly horizontally oriented, intricate, 2.5–12 μm wide hyphae, sharply delimited from underlying hyphae of trama; hyphal terminations with brownish yellow parietal pigments, usually thin-walled. Terminal cells near pileus margin (17 –) 25–35.7 – 45.5 (– 67) × (4.5 –) 8.5–14.7 – 21 (– 30) μm; clavate obpyriform or fusiform, rarely cylindrical, usually irregularly lobate, often with lateral projections, often flexuous; subterminal cells usually narrower and subcylindrical, rarely clavate or fusiform, flexuous, often branched with lateral projections or lobate. Terminal cells near pileus center (13 –) 23–32.7 – 42.5 (– 62) × (6 –) 9.5–14.7 – 19.5 (– 28) μm; mainly clavate, often ellipsoid, obpyriform or fusiform, rarely sphaeropedunculate, less frequently lobate or flexuous, occasionally with lateral projections or nodules; subterminal cells ventricose or subcylindrical, often with lateral swellings or lobate. Caulocystidia (23 –) 32.5–45.1 – 58 (– 71) × (5.5 –) 6–8.3 – 10.5 (– 15) μm; clavate, sometimes sphaeropedunculate or obpyriform, apically obtuse, usually flexuous or twisted, repent with ascending tips or erect, often irregularly oriented, individual or in small to large fascicules; thin-walled, sometimes with thickened walls up to 0.5 with μm. Clamp connections present.

Distribution and ecology.

Known from two localities in France; in grasslands, probably preferring calcareous soil.

Additional material studied.

France • Ain, Quincieu, W of Grenoble , plain pasture with only a few Crataegus oxyacantha, G. Lacombe and M. Josserand , 14 Aug 1956 ( G 00260855 ) ; • ibid., 22 Aug 1956 ( G 00260854 ) ; • Dordogne, Thénon , coord. 45°08'13"N, 01°03'57"E, grassland on calcareous soil (Mesobromion), 25 Oct 2001, G. Corriol GC 01102501 ( BBF) .

Notes.

Dermoloma hygrophorus is a member of D. subgenus Amylospora , section Atrobrunnea . It is among the most easily distinguishable species of the genus because of its large, fleshy and pale-colored basidiomata. The phylogenetically most closely related species is D. parvisporum (Fig. 2 ), which is characterized by the small mycenoid and dark colored basidiomata (see below). The morphologically most similar species is Neodermoloma campestre , but this is a North American species with more crowded lamellae and different elements in the pileipellis. The type sequence of D. hygrophorus was used by Sánchez-García et al. (2021) as the only sample of the species included in their phylogeny. The sequence is only partial and of poor quality which resulted in an unresolved position of the species within D. section Atrobrunnea . Recent collections, included in our study, allowed more precise placement of the species that is supported as sister to D. parvisporum .

Figures

Figure 2. Phylogram generated by ML analysis based on combined sequence data of ITS, LSU, rpb 1, rpb 2, mcm 7 and tef 1 a showing phylogenetic relationships within genus Dermoloma. ML bootstrap support values greater or equal to 50 % and Bayesian posterior probabilities greater or equal to 0.90 are indicated above or below the nodes. Sequences originating from type collections are labelled in red and bold.

Figure 31. Basidiomata of Dermoloma in field appearance. a Dermoloma huartii [LIP (PAM 14110907), holotype], photo D. Huart; b Dermoloma huartii [LIP (PAM 14110909)], photo D. Huart; c Dermoloma hygrophorus [BBF (GC 01102501)], photo G. Corriol; d Dermoloma intermedium (SAV F- 4270), photo S. Jančovičová; e Dermoloma intermedium (SAV F- 22209), photo S. Jančovičová; f Dermoloma intermedium [LIP (PAM 14110905)], epitype, photo P. - A. Moreau. Scale bar: 10 mm.

Figure 33. Dermoloma hygrophorus (G 00127362, holotype), microscopic elements. a Spores; b caulocystidia; c basidia and basidioles; d pileipellis elements near the pileus margin; e pileipellis elements near the pileus center. Scale bar: 5 µm for spores and 10 µm for other elements.