Dermoloma fuscobrunneum P. D. Orton

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 fuscobrunneum P. D. Orton , Notes R. bot. Gdn. Edinb. 38 (2): 326. 1980.

Figs 23 f, g , 26

Holotype.

United Kingdom • England, Somerset, Bickham Wood, Crawley , in locis graminosis vel in silvis, 24 Oct 1975, P. D. Orton 4735 ( E 16876 ).

Epitype

(designated here MBT 10022913): France • Pas-de-Calais, Ambleteuse, Pré communal , coord. 50°48'28"N, 01°37'40"E, pastured grassland on sand, 10 Nov 2014, D. Huart and P. - A. Moreau PAM 14111008 ( LIP) .

Distinguishing characters.

European species; basidiomata medium sized; pileus margin not striate; lamellae and stipes ochraceous-gray to white; spores inamyloid; caulocystidia wider than 5.5 µm.

Pileus 10–25 mm; convex, indistinctly umbonate; margin not striate; surface near margin smooth, near center radially rugulose or wrinkled, hygrophanous; color when young dark brown (6 F 4), when mature near margin brown (6 E 3), when dry grayish brown (6 D 3), near center dark brown (6 F 4), when dry grayish brown (6 E 3). Stipe 20–30 (– 50) × 2.5–4 (– 8) mm; cylindrical to slightly fusiform, narrowed towards the base, usually flexuous especially near the base; surface finely longitudinally striate, finely granulose near lamellae, finely fibrillose towards the base; color ochraceous-gray (5 B 2) to almost white. Lamellae L = 20–42, l = 3; up to 5 mm wide; adnate-emarginate and indistinctly decurrent with tooth; color ochraceous-gray (5 B 2) to almost white; edges entire or slightly irregular, rarely serrulate. Context when young elastic, later fragile; odor farinaceous.

Spores (4.5 –) 4.9–5.2 – 5.5 (– 6.1) × (3.2 –) 3.6–3.8 – 4.1 (– 4.7) μm; broadly ellipsoid to ellipsoid, Q = (1.21 –) 1.28–1.35 – 1.42 (– 1.53); walls inamyloid; hilar appendage ca. 0.5–1.5 μm long. Basidia (20 –) 23.5–26.1 – 29 (– 31) × (6 –) 6.5–6.8 – 7 (– 8) μm; clavate; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 3–7.5 μm wide. Marginal cells (13 –) 15–18.2 – 21.5 (– 26) × 2.5–3.6 – 4.5 (– 5.5) μm; not well-differentiated, cylindrical or clavate, often flexuous. Pileipellis 65–76 μm deep; suprapellis of mainly one layer of inflated cells; subpellis 24–27 μm deep, hardly differentiated, of densely packed, irregularly oriented, puzzled, 3–12 μm wide hyphae, not sharply delimited from horizontally oriented hyphae in trama; hyphal terminations with brown parietal pigments, thin-walled or occasionally thickened up to 1 μm and with dark incrusted pigments especially near septa of terminal cells and in subpellis. Terminal cells near pileus margin (22 –) 30.5–38.4 – 46 (– 56) × (9 –) 16–20.4 – 24.5 (– 33) μm; usually obpyriform, sphaeropedunculate or clavate, sometimes ellipsoid; subterminal cells usually narrower and implemented into intricate hyphae of subpellis, sometimes with lateral swellings. Terminal cells near pileus center (16 –) 26–36 – 46 (– 54) × (8 –) 12–17 – 22 (– 31) μm; similar to cells near margin; subterminal cells usually narrower, occasionally with lateral swellings or irregularly lobate. Caulocystidia (19.5 –) 25.5–37.3 – 49 (– 69) × (3 –) 5–7.1 – 9 (– 12) μm; usually clavate, sometimes cylindrical, usually not flexuous, often clustered in small ascending fascicules, sometimes individual and repent; usually with slightly thickened walls up to 0.5 μm, often with crystalline or granulose yellow incrustations. Clamp connections present.

Distribution and ecology.

Known from four localities in France, Slovakia, Spain and United Kingdom; in grasslands or forests; habitat preferences insufficiently known.

Additional material studied.

Slovakia • Podbeskydská vrchovina Mts., NW margin of the village Zákamenné , terrestrial in a meadow, 11 Oct 2012, V. Kučera ( SAV F-3860 ) . Spain • Pyrénées Mts., Canfranc, Río de la Canal Roya , coord. 42°46'26"N, 00°30'56"E, terrestrial, under Buxus sp. and Pinus sylvestris , 3 Oct 2022, S. Adamčík ( SAV F-22210 ) .

Notes.

Dermoloma fuscobrunneum is a member of D. subgenus Dermoloma , section Dermoloma . It has relatively small basidiomata which makes it similar to D. carpathicum and D. simile . It is distinguished from them by the paler or almost white lamellae and stipe, and the caulocystidia wider than 5.5 μm. The identification of species in D. section Dermoloma can be problematic and requires special attention and multisource data (see notes under D. cuneifolium ). Dermoloma fuscobrunneum was included in the phylogenetic study by Sánchez-García et al. (2021) as “ D. cf. cuneifolium ”. The species was originally distinguished from other species with inamyloid spores by prevailingly brown and not gray colors ( Orton 1980), however, our study revealed low taxonomic significance of pileus colors in D. subgenus Dermoloma (Fig. 6 ). Sequencing of the holotype specimen failed, but our morphological analysis of the type specimen confirmed that D. fuscobrunneum has inamyloid spores on av. 4.6 × 3.5 μm in size. The small spores serve to distinguish D. fuscobrunneum from D. atrocinereum , D. bellerianum , D. aff. bellerianum , D. fusipes , D. aff. fusipes , D. huartii and D. intermedium (Fig. 7 ). Dermoloma simile has similar spores but smaller basidiomata. Among the studied species, D. cuneifolium and D. carpathicum have similar spores and basidiomata sizes, but we decided to assign the name D. fuscobrunneum to a phylogenetic species previously labelled as “ D. aff. cuneifolium 2 ”, which has the colors most similar to those described in the protologue. No recent material from the country of the type origin ( United Kingdom) was available, therefore we selected a collection from northwest France as the epitype. The original description ( Orton 1980) mentioned grassy places as ecology of the type collection, but later in the description he wrote for this specimen: “ In mixed deciduous wood of recent origin ”.

Figures

Figure 6. Chromatic diagram showing variation of pileus, lamellar and stipe surfaces on Dermoloma. Colors observed on fresh basidiomata were coded and transferred from Kornerup and Wanscher (1978). These observations are presented in Suppl. material 6.

Figure 7. Density plots showing statistical differences in micromorphological characters observed in Dermoloma (D.) and Neodermoloma (N.). North American species are indicated in yellow, European species with inamyloid spores in green and European species with amyloid spores in purple. a Spore length; b spore width; c spore Q; d caulocystidia width. Average values are presented in Suppl. material 7.

Figure 23. Basidiomata of Dermoloma in field appearance. a. Dermoloma curvicystidiatum (CNF 1 / 1963), photo A. Mešić; b. Dermoloma curvicystidiatum (GLM-F 137758), photo A. Karich; c. Dermoloma fumosidiscum (TENN-F- 076389, holotype), photo M. G. Sánchez; d, e Dermoloma fumosidiscum (TENN-F- 076330), photo J. Kalichman; f Dermoloma fuscobrunneum [LIP (PAM 14111008), epitype], photo P. - A. Moreau; g Dermoloma fuscobrunneum (SAV F- 22210), photo S. Jančovičová. Scale bar: 10 mm.

Figure 26. Dermoloma fuscobrunneum (SAV F- 3860), microscopic elements. a Spores; b caulocystidia; c basidia and basidioles; d marginal cells; e pileipellis elements near the pileus margin; f pileipellis elements near the pileus center. Scale bar: 5 µm for spores and 10 µm for other elements.