Dermoloma confusum P. - A. Moreau & Courtec., 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 confusum P. - A. Moreau & Courtec. sp. nov.

Figs 20 a, b , 21

Etymology.

The epithet refers to previous confusion with D. pseudocuneifolium.

Holotype.

United Kingdom • Wales, Pembrokeshire, Upton Castle , coord. 51°42'22"N, 04°51'57"E, terrestrial in lawn, 26 Oct 2014, S. Adamčík ( SAV F-4420 ).

Diagnosis.

European species; basidiomata medium sized, collybioid; pilei and stipes brown; lamellae usually darker brownish gray or grayish brown; marginal cells clavate, lageniform or cylindrical and without projections; caulocystidia clavate or fusiform.

Pileus (7 –) 10–35 (– 40) mm; convex to plane, sometimes indistinctly umbonate, sometimes lobate, rarely obtusely conical; margin translucently striate to half of the radius, recurved when old; surface near margin smooth, near center rugulose, rough or pitted, hygrophanous; color when young dark brown (6 F 6), when mature near margin dark brown (6 F 3, 6 F 4, 7 F 3), brown (5 E 5,5E 6,6E 4,6E 5), light brown (6 D 4), when dry brown (5 E 4), grayish brown (6 D 3), brownish ochraceous (5 C 3, 5 C 4, 6 C 4), light brown (5 D 4, 5 D 6), grayish ochraceous (5 B 3), pale ochraceous (5 A 3), near center dark brown (5 F 6, 6 F 3, 6 F 4, 6 F 5, 6 F 6, 7 F 3, 7 F 4, 7 F 5), brown (5 E 4,6E 4), light brown (5 D 5), when dry brown (5 E 4,5E 5), light brown (5 D 4, 5 D 5, 5 D 6), brownish ochraceous (5 C 4, 5 C 5), rarely grayish brown (6 D 3) or dark brown (6 F 5). Stipe (10 –) 17–55 (– 63) × (1 –) 2–6 (– 7) mm; cylindrical, not distinctly narrowed towards the base, flexuous, grooved; surface finely longitudinally striate, pruinose near lamellae, towards the base shiny and glabrous; color near lamellae ochraceous-gray (5 B 2), brownish ochraceous (5 C 3), light brown (5 D 4), brownish gray (6 C 2, 6 D 2), grayish brown (6 D 3,6E 3), light brown (6 D 4), rarely brown (6 E 4), near the base dark brown (5 F 3, 5 F 5, 6 F 3, 6 F 4, 6 F 5, 7 F 4, 7 F 6), brown (5 E 4,5E 5,6E 4,6E 5), grayish brown (5 E 3, 6 D 3,6E 3), rarely brownish gray (6 D 2). Lamellae L = (18 –) 21–32 (– 38), l = 1–3 (– 7); 2–6 mm wide; adnate-emarginate, sometimes decurrent with tooth; color brownish gray (5 C 2, 6 C 2, 6 C 2, 6 D 2), grayish brown (5 D 3, 6 D 3, 7 D 3), brownish ochraceous (6 C 3, 6 C 4); edges entire. Context when young elastic, later fragile; odor farinaceous.

Spores (5.1 –) 5.5–6 – 6.5 (– 7.7) × (3.4 –) 3.7–4 – 4.3 (– 5.4) μm; ellipsoid to narrowly ellipsoid, Q = (1.27 –) 1.40–1.50 – 1.61 (– 1.85); walls amyloid; hilar appendage 0.5–1.5 μm long. Basidia (23 –) 25–29.4 – 34 (– 60) × (5 –) 6–6.5 – 7 (– 8.5) μm; clavate; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 3–6 μm wide. Marginal cells (13 –) 21–30.7 – 40.5 (– 53) × (3.5 –) 4.5–6 – 7.5 (– 9.5) μm; clavate, lageniform or cylindrical, usually flexuous, apically often constricted or appendiculate. Pileipellis 45–50 μm deep; suprapellis of mainly two layers of inflated cells; subpellis 13–20 μm deep, not well-differentiated, of densely packed, irregularly oriented, puzzled, 3–10 μm wide hyphae, not sharply delimited from horizontally oriented hyphae in trama; hyphal terminations with brownish parietal pigments, thin-walled, near septa and in subpellis with dark brown and sometimes also slightly incrusted pigments and occasionally with thickened walls up to 0.7 μm. Terminal cells near pileus margin (20.5 –) 33.5–43.9 – 54 (– 82) × (10 –) 14–19.5 – 24.5 (– 33.5) μm; usually clavate or obpyriform, sometimes sphaeropedunculate, rarely ellipsoid or subglobose; subterminal cells usually narrower and branched, cylindrical or fusiform, occasionally inflated, sometimes with lateral swellings. Terminal cells near pileus center (14.5 –) 31–46 – 60 (– 109) × (7.5 –) 13.5–20.3 – 27 (– 43.5) μm; similar to cells near margin but often flexuous and constricted towards septa; subterminal cells similar to cells near margin. Caulocystidia (10 –) 23–33.8 – 45 (– 62) × (3 –) 4.5–7.4 – 10.5 (– 17) μm; clavate or fusiform-ventricose, often flexuous, often clustered in small ascending fascicules, sometimes individual and repent; usually with slightly thickened walls up to 0.5 μm, with brownish to brown parietal pigments. Clamp connections present.

Distribution and ecology.

Mainly in temperate-montane regions of Central and Western Europe. So far known from France, Germany, Slovakia and Wales ( United Kingdom); in grasslands on calcareous soil.

Additional material studied.

France • Baives, Réserve naturelle régionale des Monts de Baives , coord. 04°11'24"E, 50°03'53"N, Oct 2008, C. Lécuru CL / F 08.245 ( LIP, as D. pseudocuneifolium ) ; Boulogne-sur-Mer, Cimetière de l’Est, grassy alley , 23 Oct 2006, A. Flahaut CL / F 06.248 ( LIP, as D. cuneifolium var. pragensis ); • Lille, jardin botanique de la Faculté de pharmacie , coord. 49°19'57"N, 02°36'08"E, urban grassland on rich calcareous soil, 13 Nov 2016, R. Courtecuisse and P. - A. Moreau PAM 16110301 ( LIP) ; • ibid., 14 Nov 2014, P. - A. Moreau PAM 14111401 ( LIP) ; • ibid., 28 Oct 2005, P. - A. Moreau PAM 05102801 ( LIP) ; • Dannes, Dunes du Mont Saint-Frieux , coord. 50°36'05"N, 01°35'17"E, 24 Oct 2013, A. Flahaut CL / F 13.234 ( LIP, as D. intermedium var. coniferarum ) . Germany • Baden-Württemberg, Justingen, Schachenheide , coord. 48°24'35"N, 09°40'25"E, terrestrial in semi-natural grassland, 3 Oct 2021, S. Adamčík ( SAV F-20913 ) ; • Rheinland-Pfalz, Sobernheim , elev. 215 m, coord. 49°47'18"N, 07°40'35"E, terrestrial in semi-natural grassland, 9 Nov 2019, C. Manz ( SAV F-20536 ) ; • ibid., 9 nov 2019, F. Hampe ( SAV F-20564 ) ; • Schleswig-Holstein, Fehmarn, Deich , 17 Nov 2015, T. Böhning AG 152 ( ELTE) . 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, S. Adamčík ( SAV F-20814 ) ; • ibid., 24 Oct 2020, S. Adamčík ( SAV F-20824 ) ; • ibid., 25 Oct 2020, M. Caboň ( SAV F-20837 ) ; • ibid., 25 Oct 2020, M. Caboň ( SAV F-20838 ) ; • ibid., 25 Oct 2020, S. Jančovičová ( SAV F-20833 ) ; • ibid., 25 Oct 2020, S. Jančovičová ( SAV F-20842 ) . United Kingdom • Wales, Pembrokeshire, Upton Castle , coord. 51°42'22"N, 04°51'57"E, terrestrial in lawn, 26 Oct 2014, S. Adamčík ( SAV F-4418 ) ; • ibid., 26 Oct 2014, S. Adamčík, ( SAV F-4422 ) .

Notes.

Dermoloma confusum corresponds to the widely accepted concept of D. pseudocuneifolium ( Arnolds 1993; Contu et al. 2008) and, as a species with amyloid spores, it is a member of D. subgenus Amylospora , section Atrobrunnea . It belongs to a larger clade of species with mainly collyboid basidiomata that includes also D. curvicystidiatum , D. griseobasale , D. phaeopodium and D. pruinosipes (Fig. 2 ). In the field it is very difficult to distinguish from other members of this clade, and especially from the very similar D. phaeopodium . A useful distinguishing character seems to be the presence of marginal cells that are cylindrical or lageniform and apically constricted or mucronate. Dermoloma pseudocuneifolium was first introduced by Herink (1958) as an invalid name (no Latin description) and later adopted by Bon (1986). Their concept was based on a misapplication of D. cuneifolium as a species with amyloid spores by Josserand (1943) based on French material. Bon (1986) designated his collection as the type and the protologue. Bon‘s notes attached to the type specimen both describe the spores as amyloid, 7.5–9 × 4–5 μm. Our type sequencing failed, but the type specimen (a single basidiome) showed bisporic basidia without clamp connections and inamyloid narrow spores on av. 5.2 × 3.5 μm, Q = 1.49. These inamyloid spores and two-spored basidia are consistent with members of the D. bellerianum complex and are contrary to the current use for a species with amyloid spores ( Wilhelm 1992; Arnolds 1993, 1995; Contu et al. 2008; Sánchez-García et al. 2021). Therefore, we here consider D. pseudocuneifolium a dubious name. Dermoloma confusum was included in the previous phylogenetic study by Sánchez-García et al. (2021) as “ D. pseudocuneifolium ”.

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 20. Basidiomata of Dermoloma in field appearance. a Dermoloma confusum (SAV F- 20536), photo S. Jančovičová; b Dermoloma confusum [LIP (PAM 05102801)], photo P. - A. Moreau; c Dermoloma cuneifolium (SAV F- 4395), photo D. Harries; d Dermoloma cuneifolium (SAV F- 4702), photo S. Jančovičová; e Dermoloma cuneifolium (SAV F- 4265), photo S. Jančovičová; f Dermoloma cuneifolium (SAV F- 23426), photo G. Friebes. Scale bar: 5 µm.

Figure 21. Dermoloma confusum (SAV F- 4420, 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.