Dermoloma curvicystidiatum Mešić, Tkalčec, Brandrud & Dima, 2025

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 curvicystidiatum Mešić, Tkalčec, Brandrud & Dima sp. nov.

Figs 23 a, b , 24

Etymology.

The epithet refers to the flexuous caulocystidia and marginal cells.

Holotype.

Germany • Rheinland-Pfalz, Horbach , elev. 370 m, coord. 49°49'44"N, 07°31'17"E, terrestrial in semi-natural grassland, 8 Nov 2019, S. Adamčík ( SAV F-20504 ).

Diagnosis.

European species; basidiomata collybioid, moderately large, brown to dark brown on all parts; pilei becoming ochraceous- brown when dry; spores amyloid, on average> 6.5 µm long and> 4 µm wide; marginal cells and caulocystidia usually flexuous and nodulose, occasionally with projections.

Pileus (7 –) 10–22 mm; broadly conical to convex, indistinctly umbonate; margin translucently striate to half of the radius; surface smooth near margin, rugulose or rough near center, hygrophanous; color near margin dark brown (6 F 7), when dry light brown (5 D 4), near center dark brown to almost black (6 F 4, 6 F 7, 7 F 4), when dry brownish ochraceous (5 C 4). Stipe (23 –) 32–44 × 1–3 mm; cylindrical, flexuous; surface finely longitudinally striate, pruinose near lamellae, glabrous towards the base; color near lamellae brown (6 E 4) to dark brown (6 F 4, 6 F 6), near the base dark brown (6 F 4, 6 F 8). Lamellae L = 17–37, l = 1–3; 3–4 mm wide; adnexed to adnate-emarginate; color brown (6 E 3,6E 4), old dark brown (6 F 5); edges entire. Context elastic; odor farinaceous.

Spores (6 –) 6.3–6.7 – 7.1 (– 7.7) × (3.8 –) 4.1–4.3 – 4.6 (– 4.8) μm; narrowly ellipsoid to oblong, Q = (1.38 –) 1.45–1.55 – 1.64 (– 1.75); walls amyloid; hilar appendage 0.5–1 μm long. Basidia (22 –) 26–29.2 – 32.5 (– 34) × (5.5 –) 6.5–6.8 – 7.5 (– 8) μm; clavate; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 4–7 μm wide. Marginal cells (18 –) 22.5–26.9 – 31.5 (– 38) × (3 –) 4–5.5 – 6.5 (– 8.5) μm; cylindrical or lageniform, rarely clavate, often very flexuous and nodulose, occasionally diverticulate or with lateral projections. Pileipellis 50–65 μm deep; suprapellis 33–43 μm deep, usually of one to three layers of inflated, loosely arranged cells; subpellis hardly defined, 20–30 μm deep, of densely packed, puzzled, 3–10 (– 15) μm wide, almost horizontally oriented hyphae and gradually passing to horizontally oriented hyphae in trama; hyphal terminations with brownish yellow to dark brown parietal pigments, and locally also with incrusted pigments in subpellis near the center, walls thickened up to 0.5 μm. Terminal cells near pileus margin (15 –) 27.5–37.8 – 48 (– 65) × (8 –) 12–16.8 – 21.5 (– 34) μm; usually obpyriform, sphaeropedunculate or clavate; subterminal cells occasionally branched, mainly fusiform and ventricose, often with lateral swellings. Terminal cells near pileus center (12 –) 26.5–35.5 – 44.5 (– 56) × (11 –) 13.5–16.7 – 20 (– 25) μm; similar to cells near margin but occasionally also ellipsoid; subterminal cells usually narrower, narrowly cylindrical or fusiform, often branched, occasionally irregularly lobate. Caulocystidia (25 –) 31–46.5 – 62 (– 102) × (3.5) 5–8.3 – 11.5 (– 17) μm; very variable in shape and size, some broadly clavate or sphaeropedunculate, others filiform and with long attenuated tips, near lamellae also flexuous-filiform and similar to marginal cells, often flexuous, sometimes lobate, in clusters or occasionally also individual, repent or ascending; usually with slightly (0.5 m) thickened walls but near septa and on subterminal cells up to 1 μm, with brownish yellow, parietal pigments. Clamp connections present.

Distribution and ecology.

Known from temperate-boreal areas in, Croatia, Finland, Germany and Norway; in semi-natural grasslands on calcareous soils, once in a calcareous, thermophilous deciduous forest.

Additional material studied.

Croatia • Zagreb, Črnomerec , coord. 45°50'04"N, 15°57'03"E, mowed grassland with short grass and mosses, 22 Oct 1998, A. Mešić ( CNF 5/269 ) ; • Zagreb, Črnomerec, coord. 45°50'01"N, 15°56'56"E, grassland with short grass and mosses, 27 Oct 2000, A. Mešić ( CNF 1/1963 ) ; • Zagreb, Črnomerec, coord. 45°49'59"N, 15°56'58"E, grassland mowed twice a year, 25 Oct 2012, Z. Tkalčec ( CNF 1/6491 ) . Finland • Åland, Mariehamn, W of Dalen, near the road to Espholmen , coord. 60°04'08.4"N, 19°57'36.0"E, herb-rich forest with Acer platanoides , Betula sp. , Corylus avellana , Fraxinus excelsior , Picea abies , on calcareous ground, 21 Aug 2000, J. Vauras FIPUT 185-14 ( TUR 140054 ) . Germany • Lückendorf, Kurwiese , coord. 50°49'53"N, 14°45'29"E, mesophilic semi-arid meadow (park-lawn), regularly mown, 1 Sep 2021, A. Karich and R. Ullrich IHI- 21 Der 01 ( GLM-F 137758 , as D. pseudocuneifolium ) . Norway • Oppland, Lunner, Kjørvensætra , in semi-natural grazed pasture on calcareous soil, Aug 2015, T. E. Brandrud TEB 061-15 ( O) ; • ibid., 10 Aug 2016, T. E. Brandrud and B. Dima DB 6031 ( ELTE), duplicate TEB 157-16 ( O) ; • Vestland, Bømlo, Spyssøya, Myra , coord. 59°43'44"N, 5°22'01"E, in semi-natural grassland on calcareous soil, 7 Oct 2022, J. B. Jordal, P. Fadnes and A. H. Abaz NOBAS 10390-23 ( O-F-259833 ) .

Notes.

Dermoloma curvicystidiatum is a member of D. subgenus Amylospora , section Atrobrunnea . It belongs to a larger clade of species with mainly collyboid basidiomata (see notes under D. confusum ). In the field it is very difficult to distinguish it from other members of this clade. It is well-defined by combination of the darker brown colors of basidiomata and the larger spores. Very closely related are D. pruinosipes and D. aff. pruinosipes , of which the former has a more distinctly pruinose stipe and the latter with marginal cells that are not nodulose and flexuous. Dermoloma curvicystidiatum is for the first time included in a phylogeny in this study.

Figures

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 24. Dermoloma curvicystidiatum (SAV F- 20504, holotype), 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.