Dermoloma rostratum 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 rostratum Mešić, Tkalčec, Brandrud & Dima sp. nov.

Figs 43 e, f , 48 a, b , 49

Etymology.

Caulocystidia and marginal cells have curved beak-like terminations.

Holotype.

Slovakia • Kremnické vrchy Mts., pasture 0.5 km W of Tajov , elev. 600 m, coord. 48°44'54"N, 19°03'31"E, terrestrial, 24 Oct 2020, M. Caboň ( SAV F-20811 ).

Diagnosis.

European species; basidiomata small, mycenoid; pilei 4–20 mm in diameter with distinctly translucently striate margin; stipes 0.5–2 mm wide; lamellae brownish gray or grayish brown; spores amyloid, 5–6 × 3.2–3.7 μm, narrowly ellipsoid to oblong; caulocystidia 4.5–8 μm wide, usually flexuous, often lobate, nodulose or diverticulate.

Pileus 4–20 (– 22) mm; conico-convex, later almost plane, sometimes indistinctly umbonate; margin translucently striate to half of the radius, sometimes indistinctly crenulate; surface smooth, near center sometimes rough or rugolose, hygrophanous; color near margin grayish brown (5 D 3,5E 3) to brown (6 E 4), near center dark brown (6 F 3, 7 F 4, 7 F 5) to almost black, when dry margin pale grayish brown, center ochre-brown. Stipe (8 –) 16–37 (– 48) × 0.5–2 (– 3) mm; cylindrical, flexuous, slightly tapering towards the base; surface when young finely pruinose all over, later almost glabrous; color near lamellae light brown (7 D 3), grayish brown (5 E 3) to brown (5 E 4), near the base dark brown (6 F 4, 7 F 4). Lamellae L = 16–28 (– 38), l = 1–3; 1–3 mm wide; adnexed to adnate-emarginate, sometimes decurrent with tooth; color brownish gray (7 C 2) or grayish brown (6 D 3); edges entire, concolorous. Context fragile; odor farinaceous or indistinct.

Spores (4.3 –) 5–5.5 – 6 (– 6.7) × (2.9 –) 3.2–3.5 – 3.7 (– 4.3) μm from collections with 4 - spored basidia and (5.4 –) 5.7–6.7 – 7.5 (– 8.1) × (3.4 –) 3.5–3.9 – 4.2 (– 4.5) μm from collections with 2 - spored basidia; narrowly ellipsoid to oblong, Q = (1.30 –) 1.45–1.59 – 1.73 (– 1.91) from collections with 4 - spored basidia and (1.40 –) 1.47–1.72 – 1.94 (– 2.03) from collections with 2 - spored basidia; walls amyloid, sometimes thick-walled and dextrinoid; hilar appendage ca. 0.5–1.5 μm long. Basidia (20 –) 23–26.3 – 29.5 (– 34) × (5 –) 6–6.1 – 7 (– 7.5) μm; clavate; usually with only 4 sterigmata, some collections with predominantly or exclusively 2 sterigmata. Basidioles first cylindrical, then clavate, ca. 3.5–6.5 μm wide. Marginal cells (16 –) 20.5–27.1 – 34 (– 40) × (4.5 –) 5–6 – 7 (– 7.5) μm; irregularly shaped, cylindrical, clavate, lageniform, fusiform, lobate, flexuous, nodulose. Pileipellis 60–80 μm deep; suprapellis 40–55 μm deep, usually of one to three layers of inflated, densely arranged cells; subpellis not well differentiated, ca. 15–35 μm deep, of densely packed, puzzled, almost horizontally oriented, 3.5–10 (– 15) μm wide hyphae, not sharply delimited from horizontally oriented hyphae in trama; hyphal terminations with brownish yellow parietal pigments, walls thickened up to 0.5 μm, near septa of terminal cells and in subpellis up to 1 μm. Terminal cells near pileus margin (21 –) 29.5–39 – 48.5 (– 70) × (10 –) 13–16.8 – 20.5 (– 32) μm; obpyriform or clavate, often flexuous towards septa; subterminal cells narrower or equally wide, often branched, ventricose, often lobate. Terminal cells near pileus center (20 –) 28.5–40.7 – 53 (– 87) × (8 –) 13–18.5 – 24 (– 38) μm; pyriform or clavate, rarely sphaeropedunculate; subterminal cells cylindrical to broadly ventricose, often with lateral swellings or irregularly lobate. Caulocystidia (11 –) 18.5–40.9 – 63.5 (– 93) × (4 –) 4.5–6 – 8 (– 14) μm; clavate, rarely cylindrical, fusiform or obpyriform, usually flexuous, often lobate, nodulose or diverticulate, sometimes moniliform, in small or large clusters, loosely arranged, irregularly oriented, interwoven; usually with slightly thickened walls up to 0.5 μm, with brownish yellow parietal and occasionally slightly incrusted pigments. Clamp connections present.

Distribution and ecology.

Widely distributed, from the Mediterranean to boreal regions. Known from Austria, Croatia, Denmark, Germany, The Netherlands, Norway and Slovakia; in semi-natural grasslands, natural, dry grasslands or forests, usually on calcareous soil.

Additional material studied.

Austria • Steiermark, Graz-Umgebung, Frohnleiten, Pöllagraben , elev. 588 m, coord. 47°17'08"N, 15°14'55"E, soil among mosses and grass, 26 Sep 2020, G. Friebes GF 20200166 ( SAV F-23430 ) . Croatia • Mljet National Park, Mljet Island, 1 km W / W-SW of Goveđari village , coord. 42°46'52"N, 17°21'03"E, forest of Erica arborea , Phillyrea latifolia , Pinus halepensis , Pistacia lentiscus and Quercus ilex , 12 Nov 2010, A. Mešić ( CNF 1/6117 ); • Mljet Island, 250 m NW / W-NW of Prožurska luka village , coord. 42°43'51"N, 17°38'442"E, hiking trail along maquis of Arbutus unedo , Myrtus communis , Pinus halepensis and Pistacia lentiscus , among mosses, 9 Nov 2009, Z. Tkalčec ( CNF 1/5694 ) ; • Zagreb, Črnomerec , coord. 45°49'57"N, 15°56'58"E, mowed grassland with short grass and mosses, 7 Oct 1998, A. Mešić ( CNF 5/209 ) . Denmark • Møn, Kongsbjerg , in natural, calcareous grassland, 17 Oct 2015, T. Læssøe and T. Smidth, DMS- 725350 ( C) . Germany • Altranft, Hütelandschaft , coord. 52°45'19"N, 14°03'42"E, in slightly calcareous extensively grazed (sheep) grassland, 6 Nov 2022, A. Karich, R. Ullrich and R. Jarling IHI- 22 Der 06 ( GLM-F 137760 ) ; • Hainewalde, Gampenstein , coord. 50°55'14"N, 14°43'22"E, loamy meadow, 23 Sep 2021, A. Karich and R. Ullrich IHI- 21 Der 02 ( GLM-F 137759 , as D. josserandii ) . The Netherlands • Beilen, nature area Schepping , in poor grassland on calcareous loam, 24 Sep 2013, E. Arnolds Arnolds 13-6 ( L, as D. cf. phaeopodium ) . Norway • Akershus, Asker, Elnestangen SV , 59°48'03"N, 10°29'53"E, in calcareous meadow / lawn, 18 Sept 2015, T. E. Brandrud, B. Dima DB 5815 ( ELTE), duplicate TEB 417-15 ( O) ; • Oslo, Oslo, Nakholmen , coord. 59°53'22"N, 10°41'40"E, in semi-natural, dry grassland close to sea, 6 Oct 2013, A. Molia and T. Læssøe NOBAS 2933-16 ( O-F-21833 ) ; • Sør-Trøndelag, Frøya, Uttian, Nordstaulvika , coord. 19°51'47"N, 07°05'12"E, calcareous sheep pasture, semi-natural meadow, 16 Sept 2021, G. Gaarder and S. M. G. Nyjordet GG 7975 ( O) ; • Telemark, Bamble, Eikstrand , coord. 59°01'51"N, 09°43'26"E, in semi-natural, dry grassland close to sea, 30 Aug 2012, A. Molia and T. Læssøe NOBAS 4369-17 ( O-F-245572 ) . Slovakia • Kremnické vrchy Mts., pasture 0.5 km W of Tajov , elev. 600 m, coord. 48°44'54"N, 19°03'30.6"E, terrestrial, 24 Oct 2020, S. Adamčík ( SAV F-20817 ) .

Notes.

Dermoloma rostratum has amyloid spores and belongs to D. subgenus Amylospora , section Atrobrunnea . The species is included in a phylogeny for the first time in this study, but it seems that it is rather widespread and probably overlooked due to the small size and basidiomata resembling species of the genus Psathyrella .

Figures

Figure 43. Basidiomata of Dermoloma in field appearance. a Dermoloma pruinosipes (GLM-F 137757), photo A. Karich; b Dermoloma aff. pruinosipes, (SAV F- 23429), photo G. Friebes; c Dermoloma pseudojosserandii [BBF (CH 17100504)], holotype, photo C. Hannoire; d Dermoloma pseudojosserandii [BBF (GC 17092306)], photo G. Corriol; e Dermoloma rostratum (SAV F- 20811, holotype), photo S. Jančovičová; f Dermoloma rostratum (SAV F- 20817), photo S. Jančovičová. Scale bar: 10 mm.

Figure 48. Basidiomata of Dermoloma in field appearance. a Dermoloma rostratum (CNF 5 / 209), photo A. Mešić; b Dermoloma rostratum (GLM-F 137760), photo A. Karich; c Dermoloma simile (SAV F- 4421, holotype), photo D. Harries; d Dermoloma simile (CNF 1 / 5620), photo A. Mešić; e Dermoloma vestigium (SAV F- 20662, holotype), photo S. Jančovičová; f Dermoloma vestigium [BBF (GC 14101103)], photo G. Corriol. Scale bar: 10 mm.

Figure 49. Dermoloma rostratum (SAV F- 20811, 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.