Dermoloma josserandii Dennis & 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 josserandii Dennis & P. D. Orton in P. D. Orton, Trans. Br. mycol. Soc. 43 (2): 226. 1960.

Figs 35 a, b , 36

Holotype.

United Kingdom • Somerset, Spaxton, Hawkridge , on soil, 15 Sep 1958, E. Marriage [ K (M) 37580 ].

Epitype.

(designated here MBT 10023010): Germany • Baden-Württemberg, Justingen, Schachenheide , coord. 48°24'35"N, 09°40'25"E, terrestrial in semi-natural grassland, 3 Oct 2021, leg. S. Adamčík ( SAV F-20907 ) .

Distinguishing characters.

European species; basidiomata medium sized; pilei 15–21 mm in diameter, near margin light brown at least when dry; stipes 2–5 mm wide; spores amyloid,> 4.3 µm wide.

Pileus (10 –) 15–21 (– 24) mm; convex, plano-convex to plane, sometimes umbonate or weakly depressed, sometimes lobate; margin indistinctly translucently striate when wet; surface rugulose, pitted or rough, sometimes smooth, slightly hygrophanous; color when young dark brown (6 F 4, 6 F 5, 7 F 4), when mature near margin light brown (5 D 4, 5 D 5), to brown (6 E 4), when dry light brown (5 D 6, 6 D 4) or grayish brown (6 C 3), near center light brown (5 D 6, 6 D 4) to brown (6 E 4,6E 5,6E 6), when dry brownish ochraceous (5 C 5) or brown (6 E 5). Stipe 20–55 × 2–5 mm; cylindrical, narrowed towards the base, often flexuous especially near the base; surface distinctly longitudinally striate and finely fibrillose especially towards the base, pruinose near lamellae; color near lamellae ochraceous-gray (5 B 2) to brownish gray (5 C 2, 6 C 2), slightly darker near the base, brownish gray (5 C 2), brownish ochraceous (5 C 3), dark blond (5 D 4) to brown (6 E 4). Lamellae L = (20 –) 24–31 (– 38), l = 0–3 (– 7); 3–8 mm wide; adnate-emarginate and decurrent with tooth; color ochraceous-gray (5 B 2, 6 B 2); edges entire or slightly irregular. Context when young elastic, later fragile; odor farinaceous.

Spores (5.5 –) 6.1–6.7 – 7.4 (– 8.7) × (4 –) 4.3–4.6 – 4.9 (– 5.4) μm; ellipsoid to oblong, sometimes slightly amygdaloid, Q = (1.24 –) 1.39–1.53 – 1.66 (– 1.86); walls amyloid; hilar appendage 0.7–1.5 μm long. Basidia (24 –) 30.5–35.1 – 39.5 (– 47) × (6 –) 6.5–7.3 – 8 (– 8.5) μm; clavate; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 3–7 μm wide. Marginal cells (14 –) 19–24.4 – 29.5 (– 38) × (3 –) 4.5–6 – 7.5 (– 10) μm; clavate or cylindrical, flexuous, occasionally slightly moniliform, nodulose or lobate, apically obtuse. Pileipellis 55–70 μm deep; suprapellis 40–50 μm deep, usually of one to three layers of inflated, densely arranged cells; subpellis not well-differentiated, ca. 10–20 μm deep, of densely packed, almost horizontally oriented, 2.5–12 μm wide hyphae, not sharply delimited from horizontally oriented hyphae in trama; hyphal terminations with brownish yellow parietal pigments, occasionally also dark brown incrusted 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 (16 –) 24.5–34.2 – 43.5 (– 68) × (8 –) 11.5–15.7 – 20 (– 29) μm; usually clavate or obpyriform, occasionally sphaeropedunculate or subglobose, sometimes with narrowed flexuous basal part; subterminal cells occasionally branched, cylindrical or clavate, rarely inflated-ventricose, occasionally with branches or lobate. Terminal cells near pileus center (15 –) 29–39.8 – 50.5 (– 69) × (9 –) 13–17.4 – 21.5 (– 33) μm; clavate or obpyriform, occasionally also shaeropedunculate, subglogose or ellipsoid, rarely lobate, often with narrowed flexuous basal part; subterminal cells usually unbranched, mainly cylindrical, occasionally fusiform-ventricose, sometimes with lateral projections or branches. Caulocystidia (18 –) 22.5–32.3 – 42 (– 61) × (3 –) 4–5.3 – 6.5 (– 10) μm; mainly narrowly clavate, occasionally cylindrical, usually fasciculated, erect or ascending; thin-walled or slightly thickened near septa up to 0.5 μm, with brownish parietal pigments. Clamp connections present.

Distribution and ecology.

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

Additional material studied.

France • Pyrénées Atlantiques, Portalet , coord. 42°48'60"N, 00°24'54"E, terrestrial in pasture, 7 Oct 2022, S. Adamčík ( SAV F-22283 ) . 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-20808 ) ; • ibid., 25 Oct 2020, M. Caboň ( SAV F-20849 ) .

Notes.

Dermoloma josserandii is a member of D. subgenus Amylospora , section Atrobrunnea . Within the section, this species forms a distinct clade with two European and two North American taxa (Fig. 2 ). European members of the clade have a distinct morphology; their basidiomata are sturdy and reminiscent of small individuals of Tricholoma , but the pileus size is relatively small. The sister species to D. josserandii is D. pseudojosserandii , which is also very similar in morphology, as they both have pale-colored lamellae and stipes and also pale brown pilei when dry. This coloration distinguishes them from the related and similar D. compactum . Dermoloma josserandii is distinguished from its sister species by more distant lamellae (L <30), stipes sometimes with darker bases, sometimes longer spores (> 6.5 μm), and marginal cells up to 8 μm wide. The concept of the name was assigned based on morphology. Despite being among the oldest published Dermoloma names ( Orton 1960), the species was not included in any previous phylogenetic study. Dermoloma josserandii was the name intended to replace the invalid name “ Tricholoma (Dermoloma) hygrophorus ” published by Josserand (1958) based on French material, but the author of this new name selected his own British collection as the type ( Orton 1960). Later, Josserand (1970) published D. hygrophorus validly, providing it with a Latin description and selecting his collection as the type. The types of these two names, however, do not represent the same species. Both species are relatively large and pale colored (Figs 5 , 6 ). We note that D. hygrophorus produces larger and pale cream- to almost white-colored basidiomata, more reminiscent of Neodermoloma than other Dermoloma species. Spores of the type specimen of D. josserandii were amyloid and on av. 6.4 × 4.4 μm in size, which is similar to the spore sizes of several other Dermoloma species. These relatively sturdy, large and pale-colored basidiomata correspond to a clade of species that are unique within D. subgenus Amylospora . Within this clade we assigned the name D. josserandii to a species with distant lamellae, in agreement with its original description (Figs 2 , 5 ). Because the type sequencing failed, and we managed to obtain only ITS from the French collection closest to the type collecting area ( United Kingdom), we selected a German specimen SAV F-20907 as the epitype, which is provided by all six DNA regions and has multiple basidiomata.

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 5. Boxplots showing statistical differences in macromorphological characters observed on Dermoloma (D.) and Neodermoloma (N.). a Pileus diameter; b stipe length; c stipe width; d lamellae number. Observations are presented in Suppl. material 6.

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 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 36. Dermoloma josserandii (SAV F- 20849), 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.