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

Figs 2 , 3 , 6

Diagnosis.

Pileus yellowish white to white with a papilla at center. Basidiospores cuboid. Pleurocystidia clavate, occasionally septate, branched, or apically protruding. Pileipellis and stipitipellis with clavate or elongated clavate terminal cells. Cystidia and hyphae of lamellar trama, pileipellis, and stipitipellis with colorless intracellular content.

Holotype.

China • Yunnan Province: Tengchong, Mingguang Town , 25.7456°N, 98.5594°E, elev. 2037 m, in the litter layer of broadleaf forest, 28 July 2022, Peng-Cheng Yuan 921 ( HKAS 150129 ).

Etymology.

Refers to the droplet-like content distributed in multiple structures, including cystidia, hyphae of the lamellar trama, pileipellis, and stipitipellis.

Description.

Basidioma small. Pileus 16–33 mm in diam., conical, convex to plano-convex, with a papilla at center; brownish (6 D 6–6 D 7), yellowish white (3 A 2) to white (1 A 1); striations indistinct, pale grey (1 B 1) to concolorous with pileus, towards the center up to 1/3–4/5 diam.; surface slightly lubricous, smooth, sometimes with tiny white tomentum at margin when young, not hygrophanous, margin undulate; context thin, white (1 A 1). Lamellae adnexed to sinuate, slightly crowded, 1–4 mm wide, with 3–5 tiers of lamellulae, narrowly ventricose, pinkish white (11 A 2), edge concolorous and sometimes serrated. Stipe 20–60 × 3–5 mm, central, cylindrical, hollow; greyish yellow (3 C 3) to olive (3 D 3) or medium grey (1 D 1,1E 1); with longitudinal or oblique striae, apex to middle with white tomentum or squamae, base slightly swollen and with white tomentum. Odor and taste not observed.

Basidiospores [95/3/3] (8.5) 9.2– 10.1 – 11.0 (12.0) × (8.0) 8.6– 9.6 – 10.4 (10.8) μm [Q = 1.00–1.13 (1.24), Q = 1.07 ± 0.05], cuboid, with 4 angles in side-view, lacking elongated angles. Basidia 48–70 × 9–17 μm, clavate, 4 - spored, colorless. Lamellar edge heterogeneous. Cheilocystidia 26–189 × 7–15 μm, elongated clavate, sometimes flexuous, hyaline or with pale yellowish green droplet-like content, thin-walled. Pleurocystidia 18–56 × 3–10 μm, clavate, occasionally septate, branched, or apically protruding, hyaline, occasionally with droplet-like content, thin-walled. Lamellar trama regular, made up of cylindrical hyphae 5–18 μm diam., smooth, thick-walled, with droplet-like content. Pileipellis a cutis composed of cylindrical and fusiform hyphae 3–11 μm wide, thin-walled; terminal cells clavate, 20–88 × 4–15 μm; both hyphae and terminal cells in pileipellis with colorless droplet-like intracellular content. Stipitipellis composed of longitudinally arranged, cylindrical hyphae 3–13 μm wide; terminal cells clavate to elongated clavate, 24–71 × 4–17 μm; both hyphae and terminal cells in stipitipellis with colorless droplet-like intracellular content. Clamp connections present in all tissue. Refractive hyphae not observed.

Habitat.

Solitary in the litter layer of broadleaf forests, sometimes with moss.

Known distribution.

Yunnan Province, China.

Additional materials examined.

China • Yunnan Province: Tengchong, Mingguang Town , 25.7456°N, 98.5594°E, elev. 2037 m, in the litter layer of broadleaf forest, 28 July 2022, Xue-Ping Fan 350 ( HKAS 150130 ) ; • Honghe Hani and Yi Autonomous Prefecture, Hekou Yao Autonomous County , elev. 2000 m, in the litter layer of broadleaf forest dominated by Fagaceae , 22 August 2019, Yun-Jiao Lüli 532532 MF 0183 ( HKAS 107829 ) .

Notes.

Entoloma guttuliferum is characterized by a yellowish-white to white pileus bearing a papilla and exhibiting indistinct striations, cuboid spores, and cystidia and hyphae of the lamellar trama, pileipellis, and stipitipellis with contents. Entoloma guttuliferum clusters with five species ( E. lacticolor , E. murrayi , E. submurrayi , E. acutiflavum , and E. quadratum ) in the phylogenetic tree. Among them, E. lacticolor is also similar to E. guttuliferum morphologically, but the former lacks pleurocystidia and has a sterile lamellar edge. Except for E. lacticolor , the other four species can be easily distinguished by the color of their basidiomata ( Selby et al. 1859; Horak 1976; He 2012; Chen et al. 2024). Entoloma albogracile and E. dennisii share similarities with E. guttuliferum in pileus color and shape. However, E. albogracile differs in having pink to porphyry-pink lamellae, pigmentless cheilocystidia and pileipellis, and the absence of clamp connections. Entoloma dennisii has smaller spores (5.5–7 μm) and pigmentless cheilocystidia ( Horak 1976). In addition, E. album and E. caribaeum also resemble E. guttuliferum , although the color of their pilei tends to be white. Compared to the new species, they lack pleurocystidia. Furthermore, the hyphae in the pileipellis of E. album lack contents. Entoloma caribaeum has larger spores with elongated angles (15–18 × 15–20 μm) and 2 - spored basidia ( Karstedt et al. 2024; Sato et al. 2025).

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 6. Microscopic features of Entoloma guttuliferum (HKAS 150129, holotype). a. Basidiospores; b. Pleurocystidia; c. Basidia; d. Cheilocystidia; e. Pileipellis; f. Stipitipellis. Scale bars: 10 μm (a – d); 20 μm (e, f).