Dermoloma griseobasale Mešić, Tkalčec & Corriol sp. nov.

Figs 27 d – f, 30

Etymology.

In reference to the dark gray brown stipe base.

Holotype.

Romania • Trascaului Mts., pasture 1 km NE of Rimetea, elev. 550–650 m, coord. 46°27'44"N, 23°34'50"E, terrestrial under Pyrus communis, 27 Sep 2015, S. Adamčík (SAV F-4723).

Diagnosis.

European species; basidiomata medium sized colybioid; pilei 7–20 mm in diameter; stipes 1–3.5 mm wide, pruinose near lamellae, grayish brown to dark brown near bases; lamellae relatively pale, brownish ochraceous-white, ochraceous-gray, brownish gray to brownish ochraceous; spores amyloid; marginal cells clavate and often lobate or with lateral projections; caulocystidia 5–10 μm wide.

Pileus 7–20 (– 22) mm; convex to plano-convex, soon expanding to plane, indistinctly umbonate; margin not striate or sometimes translucently striate up to 2 / 3 of the radius; surface smooth, sometimes rugulose or slightly veined near center, hygrophanous; color when young dark brown (6 F 6, 6 F 7), when mature near margin brown (5 E 4,5E 6,6E 4), when dry grayish brown (5 E 5, 6 D 3,6E 3), near center dark brown (5 F 4, 6 F 4, 6 F 6, 6 F 8) or yellowish brown (5 E 5), when dry brownish ochraceous (5 C 4). Stipe (15 –) 17–37 (– 54) × 1–3.5 mm; cylindrical, narrowed towards the base, flexuous; surface pruinose near lamellae, finely fibrillose or smooth and shiny towards the base; color near lamellae light brown (5 D 4), grayish brown (5 D 3,6E 3), brown (5 E 6), near the base grayish brown (5 E 3,6E 3), dark brown (6 F 4, 6 F 5, 6 F 6, 7 F 4). Lamellae L = (11 –) 13–32, l = 1–3; 2–5 mm wide; adnate-emarginate and decurrent with tooth; color ochraceous-white (5 A 2), ochraceous-gray (5 B 2), brownish gray (5 C 2) to brownish ochraceous (5 C 3); edges entire or slightly irregular. Context when young elastic, later fragile; odor farinaceous.

Spores (4.6 –) 5.3–6.1 – 7 (– 9.4) × (3.5 –) 3.7–4.1 – 4.4 (– 5) μm; ellipsoid to oblong, Q = (1.27 –) 1.37–1.49 – 1.61 (– 1.92); walls amyloid; hilar appendage ca. 0.5–1.5 μm long. Basidia (22 –) 26–29.3 – 32.5 (– 37) × (4 –) 6–6.3 – 7 (– 7.5) μm; clavate; with 4 sterigmata. Basidioles first cylindrical, then clavate, ca. 2–6.5 μm wide. Marginal cells (13 –) 16.5–21.2 – 25.5 (– 30) × (3.5 –) 6–7.8 – 9.5 (– 12) μm; usually clavate, often irregularly lobate, sometimes with short outgrowths. Pileipellis 50–60 μm deep; suprapellis of mainly one or two layers of inflated cells, loosely arranged and forming disconnected clusters near surface; subpellis not well-differentiated, of 3–15 μm wide hyphae gradually passing to horizontally oriented hyphae in trama; hyphal terminations with brownish and sometimes also dark brown parietal pigments, locally also with incrusted pigments, thin-walled or occasionally thickened up to 1 μm, especially near septa of terminal cells. Terminal cells near pileus margin (16 –) 35.5–46.7 – 58 (– 82) × (10 –) 16–24 – 32 (– 66) μm; usually sphaeropedunculate or obpyriform, sometimes with one or two constrictions near septa; subterminal cells usually narrower or more inflated and usually equally long, often branched. Terminal cells near pileus center (23.5 –) 36–46 – 56 (– 75) × (13 –) 17–23 – 28.5 (– 43) μm; usually sphaeropedunculate or clavate, sometimes obpyriform, rarely almost cylindrical with central constriction, often lobate or with lateral outgrowths; subterminal cells usually narrower, cylindrical or fusiform, usually not inflated, often branched. Caulocystidia (10.5 –) 19–30.1 – 41 (– 76) × (3 –) 5–7.3 – 10 (– 17) μm; usually clavate, sometimes cylindrical, often slightly flexuous, sometimes lobate, often clustered in small ascending fascicules, sometimes individual and repent; usually with slightly (1 μm) thickened walls especially near septa, with brownish parietal pigments. Clamp connections present.

Distribution and ecology.

Widely distributed in Europe and probably relatively common, known from Austria, Croatia, France, Germany, Italy, Romania and Slovakia; in oligothrophic (non-fertilized) semi-natural grasslands, probably preferring calcareous soil.

Additional material studied.

Austria • Steiermark, Rabenstein S of Frohnleiten, elev. 481 m, coord. 47°14'56"N, 15°18'23"E, 26 Sep 2020, G. Friebes GF 20200173 (SAV F-23427). Croatia • Ličko Lešće, near Ramljani village, Podkoren area, coord. 44°45'31"N, 15°23'01"E, rocky semi-natural grassland with sparse shrubs of Juniperus communis, A. Mešić (CNF 5/287); • Zagreb, Črnomerec, coord. 45°50'04"N, 15°57'03"E, mowed grassland with short grass and mosses, 6 Nov 1998, A. Mešić (CNF 5/297); • Zagreb, Črnomerec, coord. 45°50'04"N, 15°57'03"E, grassland mowed twice a year, 25 Oct 2012, Z. Tkalčec (CNF 1/6490). France • Hautes-Pyrénées, Castet de Gerde, coord. 43°03'35"N, 00°09'54"E, Cynosurion, 20 Oct 2007, G. Corriol GC 07102002 (BBF, as D. hygrophorus); • ibid., 2 Nov 2010, G. Corriol GC 10110201 (BBF, as D. pseudocuneifolium); • Pyrénées Atlantiques, Portalet, coord. 42°48'60"N, 00°24'54"E, terrestrial in extensively grazed pasture, 7 Oct 2022, M. Caboň (SAV F-22284). Germany • Mittelherwigsdorf, Katzenlehne, coord. 50°55'29"N, 14°44'47"E, on loamy soil in tall grass on a sun-exposed, frequently mown ancient meadow, 2 Oct 2022, A. Karich IHI- 22 Der 03 (GLM-F 137753). Italy • Genova, San Martino di Nuoto, Oliveto, 19 Nov 2011, F. Bocianolo G 2434 (GDOR, as D. cuneifolium); • Savona, Sassello, Periaschi, 2. Nov 2013, F. Bocianolo G 3183 (GDOR, as D. phaeopodium). Slovakia • Biele Karpaty Mts., 2.5 km NW of Zlatovce, coord. 48°54'37"N, 18°00'14"E, elev. 223 m, terrestrial in semi-natural grassland, 17 Sep 2014, V. Kautman (SLO 692); • ibid., 17 Sep 2014, V. Kautman (SLO 694); • Laborecká vrchovina Mts., 1.5 km NNE of Svetlice, elev. 390 m, coord. 49°11'03"N, 22°02'38"E, terrestrial in pasture, 23 Oct 2007, S. Adamčík (SAV F-4151).

Notes.

Dermoloma griseobasale has amyloid spores and belongs to D. subgenus Amylospora, section Atrobrunnea. Most cyllybioid members of the section together with D. griseobasale, form a well-supported clade of morphologically similar species (Fig. 2). Within this clade, D. griseobasale is placed in an isolated phylogenetic position. Morphologically, it is very similar to D. confusum, D. phaeopodium and other members of the clade and its identification requires special attention. We therefore recommend to use the heat map (Fig. 4), the chromatogram (Fig. 6), the key and other data available in this study, and in case of uncertainty, combine them with an ITS sequence. This species was included in the phylogenetic study by Sánchez-García et al. (2021) as “ D. cf. pseudocuneifolium like ”.