Dermoloma vellingae Adamčík & Matheny, 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 vellingae Adamčík & Matheny sp. nov.

Figs 51 a , 52

Etymology.

Named in honor of the collector, Dr. Else Vellinga, a distinguished Dutch and North American mycologist.

Holotype.

USA • Tennessee, Cocke County, Great Smoky Mountains National Park, Maddron Bald Trail , on acidic soil in mixed forest dominated by Tsuga , Quercus , Betula , Rhododendron , 10 Oct 2010, E. C. Vellinga ECV 4208 ( TENN-F-065324 ) .

Diagnosis.

North American species; basidiomata small to moderately large; pilei 11–22 mm in diameter, mainly brown to dark brown; stipes 2.5–3 mm wide; spores amyloid, 4.3–4.8 μm wide; basidia <25 µm long and <6.5 µm wide.

Pileus 11–22 mm; plano-convex, umbonate; margin not striate; surface smooth, hygrophanous; color dark brown (6 F 5) to brown (5 F 7), paler at margin. Stipe 20–30 × 2.5–3 mm; cylindrical; surface finely longitudinally striate, finely granulose near lamellae; color pale grayish, towards the base brownish gray when wounded or old. Lamellae L = 27–30, l = 3; up to 4 mm wide; emarginate; color pale gray; edges entire. Context when young elastic, later fragile; odor slightly sweetish like apple.

Spores (5.4 –) 6.1–6.5 – 6.8 (– 7.1) × (4.2 –) 4.3–4.5 – 4.8 (– 5.1) μm; ellipsoid to narrowly ellipsoid, Q = (1.23 –) 1.36–1.43 – 1.51 (– 1.67); walls amyloid; hilar appendage ca. 0.5–1 μm long. Basidia (19 –) 20.5–23.4 – 26 (– 27) × (5 –) 5.5–6.4 – 7 μm; clavate, flexuous near the base; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 3.5–6 μm wide. Marginal cells (11 –) 12–15.9 – 19.5 (– 27) × (4.5 –) 5–5.9 – 6.5 (– 7.5) μm; mainly clavate, often slightly flexuous or moniliform. Pileipellis 40–65 μm deep; suprapellis 30–45 μm deep, of one or two layers of inflated, densely arranged cells; subpellis 12–17 μm deep, hardly defined, of densely packed, horizontally oriented, 2–7 (– 10) μm wide hyphae, gradually passing to horizontally oriented hyphae in trama; hyphal terminations with brownish parietal pigments but near septa darker brown and incrusted pigments, thin-walled or with slightly thickened walls up to 1 μm, hyphae in subpellis often with thickened walls up to 1.5 μm. Terminal cells near pileus margin (25 –) 30.5–40 – 49.5 (– 58) × (10.5 –) 13.5–17.1 – 20.5 (– 26) μm; mainly sphaeropedunculate and with very narrow basal part (constricted to 2.5–4 μm), occasionally obpyriform or clavate, sometimes lobate especially towards septa; subterminal cells usually narrower, branched and implemented in subpellis, inflated and fusiform-ventricose, often lobate. Terminal cells near pileus center (20 –) 24–29.4 – 35 (– 38) × (11 –) 13.5–15.9 – 18.5 (– 22) μm; usually obpyriform or clavate, less frequently sphaeropedunculate, sometimes slightly flexuous towards bases; subterminal cells narrower or equally wide, less frequently branched, often with lateral swellings, projections or irregularly lobate. Caulocystidia (25.5 –) 43.5–64.4 – 85 (– 105) × (3 –) 3.5–5.2 – 6.5 (– 8.5) μm; mainly clavate, rarely subcylindrical, flexuous, individual or clustered in small fascicules, repent and usually with ascending tips; thin-walled, with brownish yellow parietal pigments. Clamp connections present.

Distribution and ecology.

Known from a single locality in Tennessee, USA.

Notes.

Dermoloma vellingae is a member of D. subgenus Amylospora , section Atrobrunnea . It is a member of a distinct clade that includes D. josserandii and other taxa with relatively sturdy collybioid and pale-colored basidiomata. The North American species D. appalachianum and D. hymenocephalum are also members of this clade. Dermoloma appalachianum differs from D. vellingae by the longer spores. However, D. hymenocephalum is very similar and its morphological delimitation will require more observations, including new collections. Dermoloma vellingae was included in the phylogenetic study by Sánchez-García and Matheny (2017) as Dermoloma sp. and later in Sánchez-García et al. (2021) as “ Dermoloma sp. 9 ”. The ITS region was very difficult to sequence, probably due to complex secondary structure, and this is probably the reason why this species has not appeared in any public sequence database. Because the collection presented here is well-documented and morphologically distinct, we describe it as new.

Figures

Figure 51. Basidiomata of Dermoloma in field appearance. a Dermoloma vellingae (TENN-F- 065324, holotype), photo E. C. Vellinga; b Neodermoloma campestre (TENN-F- 074505, holotype), photo P. B. Matheny. Scale bar: 10 mm.

Figure 52. Dermoloma vellingae (TENN-F- 065324, 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.