Entoloma rufosquamulosum Z. W. Liu, Y. Y. Cui & Zhu L. Yang, 2025

Liu, Ze-Wei, Li, Jing, Yang, Zhu L. & Cui, Yang-Yang, 2025, Four new species of Entoloma subgen. Cubospora (Entolomataceae, Agaricales) from Yunnan Province, China, MycoKeys 124, pp. 331-356 : 331-356

Entoloma rufosquamulosum Z. W. Liu, Y. Y. Cui & Zhu L. Yang sp. nov.

Figs 2 , 3 , 7

Diagnosis.

Pileus reddish with densely reddish brown or greyish violet squamae at center, becoming sparse towards margin. Basidiospores cuboid. Upper hyphae and terminal cells in pileipellis with reddish brown intracellular pigment.

Holotype.

China • Yunnan Province: Nujiang Lisu Autonomous Prefecture, Fugong County , elev. 1750 m, in the litter layer of evergreen broad-leaved forest, 14 August 2023, Zhu L. Yang 7052 ( HKAS 130186 ).

Etymology.

Refers to the pileus with densely reddish squamae.

Description.

Basidioma small. Pileus 10–30 mm in diam., broadly conical to campanulate; violet brown (10 E 7) when young, becoming dull lilac (16 C 3), greyish magenta (13 E 4), or reddish brown (8 E 6) at center with age, disc paler to greyish lilac (16 C 2), greyish brown (8 D 3), reddish brown (8 D 4), or greyish ruby (12 C 3); striations none in most of specimens, occasionally present but indistinct, towards the center up to 1/3 to 3/4 diam.; surface dry, with densely reddish brown (8 E 7), greyish ruby (12 E 5) or greyish violet (18 E 5) squamae at center, becoming radial and gradually sparse towards margin, not hygrophanous, margin undulate, occasionally rimose and uplifted. Lamellae adnate to sinuate, crowded, 1–3 mm wide, with 1–3 tiers of lamellulae, narrowly ventricose, white to yellowish white (2 A 2), with pinkish tinged at age, edge serrate and concolorous. Stipe 22–114 × 3–6 mm, central, cylindrical, hollow, usually tapering upwards; greyish orange (5 B 3), reddish white (9 A 2), or greyish brown (8 D 3), sometimes with reddish brown (8 D 4) bruises; nearly smooth, sometimes with tiny granular squamules, with longitudinal or oblique striae, base slightly swollen and with white tomentum. Odor and taste not observed.

Basidiospores [110/4/4] (9.0) 9.4– 10.3 – 11.2 (11.8) × (8.3) 8.9– 9.7 – 10.6 (11.0) μm [Q = 1.00–1.14 (1.18), Q = 1.06 ± 0.04], cuboid, most with 4 angles in side-view, rarely with 5 angles, lacking elongated angles. Basidia 37–59 × 12–18 μm, clavate, 4 - spored, colorless. Lamellar edge heterogeneous. Cheilocystidia 21–98 × 6–13 μm, clavate to elongated clavate, sometimes flexuous or furcate, with pale yellowish green droplet-like content or hyaline, thin-walled. Pleurocystidia absent. Lamellar trama regular, made up of cylindrical hyphae 3–15 μm diam., smooth, thin-walled, sometimes with droplet-like content. Pileipellis a cutis composed of cylindrical hyphae 3–20 μm wide, thin-walled; terminal cells clavate or fusiform, 27–111 × 6–17 μm; both upper hyphae and terminal cells in pileipellis with reddish brown intracellular pigment, lower hyphae with colorless intracellular content. Stipitipellis composed of longitudinally arranged, cylindrical hyphae 3–17 μm wide; terminal cells sparse, elongated cylindrical, 44–68 × 9–13 μm; both hyphae and terminal cells in stipitipellis with colorless intracellular content. Clamp connections present in all tissue. Refractive hyphae occasionally occur in lamellar trama and pileipellis.

Habitat.

Solitary or scattered in the litter layer of evergreen broad-leaved forest, coniferous forest dominated by Keteleeria fortunei , or mixed broadleaf-conifer forests.

Known distribution.

Yunnan Province, China.

Additional materials examined.

China • Yunnan Province: Tengchong, Zhonghe Town , elev. 1970 m, in the litter layer in coniferous forest dominated by Keteleeria fortunei , 13 August 2010, Yan-Jia Hao 242 ( HKAS 69226 ) ; • Mingguang Town , 25.7456°N, 98.5594°E, elev. 2037 m, in the litter layer of broadleaf forest, 28 July 2022, Peng-Cheng Yuan 917 ( HKAS 143019 ) ; • Diantan Town , 25.2936°N, 98.4506°E, elev. 2170–2220 m, in the litter layer of broadleaf-conifer forest, 27 July 2022, Xue-Ping Fan 316 ( HKAS 136639 ) ; • Baoshan, Longyang District , 25.2996°N, 98.7855°E, elev. 2200 m, in the litter layer of broadleaf-conifer forest, 7 August 2022, Xue-Ping Fan 540 ( HKAS 150126 ) ; • Longling County , 24.7789°N, 98.7931°E, elev. 1950 m, in the litter layer of broadleaf-conifer forest, 29 August 2022, Xue-Ping Fan 769 ( HKAS 150125 ) ; • Longling County , 24.9478°N, 98.6108°E, elev. 2050 m, in the litter layer of broadleaf-conifer forest, 1 September 2022, Xue-Ping Fan 931 ( HKAS 150124 ) .

Notes.

Entoloma rufosquamulosum is characterized by its pileus with reddish or violet squamules and cuboid spores. E. rufosquamulosum forms a stable clade with E. bichromum , E. carneum , E. pallidoflavum , E. phlebophyllum , E. plicatum , and E. tomentosum in the phylogenetic tree. Among them, E. phlebophyllum resembles E. rufosquamulosum when young, but the former has a pileus with a depressed center at maturity, a sterile lamellar edge, and a pileipellis with encrusted pigment ( Chen et al. 2024). Entoloma carneum has been reported to have a pale carneous pileus with a red center and radiating fibers, but it differs greatly from E. rufosquamulosum in microstructure, including smaller spores, the presence of pleurocystidia, and the absence of clamp connections ( Bi et al. 1986). Entoloma bichromum , E. pallidoflavum , E. plicatum , and E. tomentosum can be easily distinguished from E. rufosquamulosum by the distinctly different colors of the pileus and stipe ( Horak 1976; Largent et al. 2013; Chen et al. 2024). In addition, three species from Brazil — E. arenicola , E. vinososquamulosum , and E. voltavelhense — are similar to E. rufosquamulosum macroscopically. However, they have smaller spores or straw-yellow intracellular pigment in the pileipellis ( Karstedt et al. 2024).

Figures

Figure 2. Basidiospores of four new species of Entoloma subg. Cubospora under SEM. a, b. E. acutiflavum HKAS 150128, holotype; c, d. E. bichromum HKAS 150132, holotype; e, f. E. guttuliferum HKAS 150129, holotype; g, h. E. rufosquamulosum HKAS 130186, holotype. Scale bars: 2 μm.

Figure 3. Basidiomata of four new species of Entoloma subg. Cubospora. a, b. E. acutiflavum HKAS 150128, holotype; c, d. E. bichromum (c) HKAS 150131, (d) HKAS 150132, holotype; e, f. E. guttuliferum HKAS 150129, holotype; g, h. E. rufosquamulosum HKAS 130186, holotype. Scale bars: 10 mm.

Figure 7. Microscopic features of Entoloma rufosquamulosum (HKAS 130186, holotype). a. Basidiospores; b. Basidia; c. Cheilocystidia; d. Pileipellis; e. Stipitipellis. Scale bars: 10 μm (a – c); 20 μm (d, e).