Dermoloma magicum Arnolds

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 magicum Arnolds , Persoonia 17 (4): 665. 2002.

Figs 35 c, d , 37

Holotype.

Netherlands • Limburg, Epen, Cotessen , 21 Oct 1995, E. Arnolds 6701 ( L).

Epitype

(designated here MBT 10023011): Slovakia • Laborecká vrchovina Mts., pasture 1 km NW of Vyšná Jablonka , elev. 400–450 m, coord. 49°09'31"N, 22°06'18"E, terrestrial under Pinus sylvestris , 21 Sep 2006, J. Terray ( SAV F-4142 ) .

Distinguishing characters.

European species; basidiomata large; context blackening where bruised; spores amyloid, narrowly ellipsoid to oblong, sometimes amygdaloid, 6.8–8 × 4.1–4.7 μm.

Pileus (22 –) 29–43 (– 60) mm; convex to plane, indistinctly umbonate, sometimes lobate; margin indistinctly translucently striate when wet; surface smooth near margin, radially veined or rugulose near center, matt, hygrophanous; color near margin dark brown (6 F 5), brown (5 E 3) to grayish brown (5 D 3), when dry brownish ochraceous (5 C 3), brownish gray (5 C 2) to ochraceous-gray (5 B 2), near center dark brown (6 F 3, 6 F 5, 6 F 6), when dry brown (5 E 5), grayish ochraceous (5 B 3) to ochraceous-white (5 A 2). Stipe (35 –) 48–57 (– 70) × 4–12 (– 17) mm; cylindrical, attenuated towards the base, flexuous especially near the base; surface finely longitudinally striate, pruinose near lamellae, towards the base fibrillose or squamulose; color near lamellae grayish ochraceous (5 B 3), ochraceous-gray (5 B 2) to almost white, near the base brown (5 E 5–5 E 8) to dark brown (6 F 4). Lamellae L = 24–31 (– 44), l = 1–7; 4–8 mm wide; adnate-emarginate and decurrent with tooth; color ochraceous-white (5 A 2), ochraceous-gray (5 B 2) or brownish gray (5 C 2); edges irregular, sometimes with darker granules near stipe. Context turning black in pileus, inside of stipe turning apricot (5 B 6) to golden yellow (5 B 7); when young compact, later fragile; odor indistinctly farinaceous.

Spores (6.2 –) 6.8–7.4 – 8 (– 9.4) × (3.6 –) 4.1–4.4 – 4.7 (– 5.3) μm; narrowly ellipsoid to oblong, sometimes amygdaloid, Q = (1.43 –) 1.57–1.69 – 1.80 (– 1.96); walls amyloid, sometimes dextrinoid; hilar appendage ca. 0.5–1.5 μm long. Basidia (25 –) 29–33.1 – 37 (– 42) × (6 –) 6.9–7.6 – 8.2 (– 9) μm; clavate, flexuous near the base; with 4 sterigmata, towards edges also with 1 or 2 sterigmata. Basidioles first cylindrical, then clavate, ca. 2.5–7 μm wide. Marginal cells (12 –) 16.5–21.7 – 27 (– 37) × (3 –) 3.5–4.5 – 5.5 (– 6.5) μm; cylindrical, lageniform or lageniform-clavate, apically often nodulose, diverticulate or furcate, flexuous. Pileipellis 45–70 μm deep; suprapellis of mainly one, occasionally two layers of inflated cells; subpellis 18–35 μm deep, hardly defined, of densely packed, irregularly oriented, intricate, 3–10 (– 15) μm wide hyphae, gradually passing to horizontally oriented hyphae in trama; hyphal terminations with brownish parietal pigments, thin-walled, hyphae in subpellis often with thickened walls up to 1 μm and locally with dark incrusted pigments. Terminal cells near pileus margin (14 –) 27–38.1 – 49 (– 78) × (8 –) 11.5–15.8 – 20.5 (– 35) μm; usually clavate, sphaeropedunculate or obpyriform, rarely ellipsoid, sometimes lobate; subterminal cells usually narrower, often branched, cylindrical and occasionally with lateral swellings or lobate. Terminal cells near pileus center (14 –) 24–35.6 – 47.5 (– 71) × (6 –) 9–13.1 – 17.5 (– 31) μm; usually clavate or sphaeropedunculate, rarely obpyriform, sometimes flexuous or lobate; subterminal cells narrower or occasionally equally wide, often branched, often with lateral swellings, projections or irregularly lobate. Caulocystidia (19 –) 27–35.9 – 45 (– 78) × (3 –) 5–7.1 – 9.5 (– 13) μm; sphaeropedunculate, clavate or cylindrical, flexuous, clustered in loose fascicules and repent but locally in dense fascicules and ascending or erect; usually with slightly thickened walls up to 0.5 μm, with brownish parietal pigments but locally also dark brown, towards septa usually with brownish but locally dark brown to black incrustations. Clamp connections present.

Distribution and ecology.

Known from France, Germany, Slovakia and United Kingdom; in semi-natural grasslands on calcareous soil.

Additional material studied.

Croatia • Crni Lug, Gorski kotar area , coord. 45°25'02"N, 14°42'22"E, mowed grassland mostly with short grass, 4 Oct 1998, A. Mešić ( CNF 5/198 ) . Slovakia • Oravské Beskydy Mts., Oravská Polhora, 2 km E of Slaná voda, around the peatbog , elev. 745–755 m, coord. 49°31'40"N, 19°28'23"E, terrestrial in semi-natural grassland, 21 Jul 2020, M. Caboň ( SAV F-20618 ) . United Kingdom • Wales, Pembrokeshire, Somerton farm , coord. 51°39'83"N, 04°59'49"E, 14 Oct 2019, pasture, D. Harries DH 19-10 ( SAV F-23434 ) ; • Wales, Plas Tirion , 22 Sep 2004, G. Griffith GG 220904 ( ABS) ; • Wales, Powys, Gregynog grounds , coord. 52°34'04"N, 03°21'06"E, terrestrial in lawn, 19 Oct 2014, S. Adamčík ( SAV F-4347 ) .

Notes.

Dermoloma magicum has amyloid spores and basidiomata bruising black where handled, characters that define D. section Nigrescentia . It is the only known member of the section and because of the unique blackening context it is easily distinguishable from the other Dermoloma species. The species was included in the phylogenetic study by Sánchez-García et al. (2021) and correctly labeled as the only member of D. section Nigrescentia . Both multilocus phylogenies in this study do not support this species as a member of D. subgenus Amylospora . The species name D. magicum was assigned based on morphological match. During the preparation of the manuscript we managed to receive a partial ITS sequence of the type collection, which is not included in the ITS tree (Suppl. material 8), but does match other sequences assigned to the species and confirms the concept presented here. Spores of the type collections (av. 6.7 × 4.1 μm) were slightly smaller than in other more recent collections, but the range established by Arnolds (2002) perfectly matches our observations (Suppl. material 7). A Slovak collection was selected as epitype because it is perfectly documented and is the only collection represented by all six genes in the phylogeny.

Figures

Figure 35. Basidiomata of Dermoloma in field appearance. a Dermoloma josserandii (SAV F- 20808, epitype), photo S. Jančovičová; b Dermoloma josserandii (SAV F- 20907, epitype), photo V. Shapkin; c Dermoloma magicum (SAV F- 4142, epitype), photo S. Jančovičová; d Dermoloma magicum (SAV F- 20618), photo S. Jančovičová; e Dermoloma murinellum [LIP (PAM 06090203)], photo P. - A. Moreau; f Dermoloma obscurum (SAV F- 20012, holotype), photo S. Jančovičová. Scale bar: 10 mm.

Figure 37. Dermoloma magicum (SAV F- 4142, epitype), 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.