Entoloma orientosinense J. Q. Yan, L. G. Chen & S. N. Wang, 2025

Chen, Lin-Gen, Chen, Hong, Ding, Ling, Xu, Yu-Qin, Zeng, Hui, Wang, Sheng-Nan & Yan, Jun-Qing, 2025, Four new species of Entoloma subgenus Cyanula (Entolomataceae, Agaricales) from subtropical regions of China, MycoKeys 116, pp. 303-325 : 303-325

Entoloma orientosinense J. Q. Yan, L. G. Chen & S. N. Wang sp. nov.

Fig. 2

Etymology.

Refers to its type specimen originating from the eastern regions of China.

Holotype.

China • Anhui Province, Chizhou City, Shitan County, Guniujiang Nature Reserve , 30.0303°N, 117.5290°E, alt. 783 m, 9 October 2019, collected by Yu-Peng Ge, HFJAU 1414 .

Diagnosis.

Entoloma orientosinense is mainly characterized by the white, collybioid basidiomata, fibrillous and not striate pileus, narrow, adnate to decurrent lamellae, glabrous stipe, 5–6 angled basidiospores, sterile lamellae edge of carneogriseum-type, cylindrical to subclavate cheilocystidia, absence of cell pigments and clamp connections in hyphae. It differs from E. albinellum by its non-striate pileus, adnate to decurrent lamellae, and smaller basidiospores.

Macromorphology.

Basidiomata rather small, collybioid. Pileus 8–20 mm wide, convex then flattened with depressed center, with entire margin, slightly hygrophanous, fibrillous when young, then repent or raised scaly, not translucently striate, white (3 A 1–2). Lamellae moderately distant, 1.5–2.0 mm wide, with three types of lamellulae, adnate to decurrent, subventricose, initially white, then pink (11 B 4–6), with serrulate and concolourous edge. Stipe 20–25 × 2.0–3.0 mm, central, terete, tapered upwards, hollow, concolorous or paler with the pileus, minutely tomentose in the upper part elsewhere smooth and glabrous, base with white tomentum. Context thin, concolorous to the surface. Odor indistinct, taste not tested.

Micromorphology.

Basidiospores (8.5) 9.3–11.0 (12.5) × (6.0) 6.5–8.0 (9.0) μm, (av = 10.1 × 7.3 μm), Q = 1.2–1.6 (1.7) (Qm = 1.4 ± 0.07, n = 200), heterodiametrical, 5–6 angles in profile view, thick-walled, inamyloid. Basidia 40–52 × 11–13 μm, clavate, 4 - spored, sterigmata 5.0–10 μm long, clampless. Pleurocystidia absent. Lamellae edge sterile of carneogriseum-type. Cheilocystidia regularly dispersed in the lamellae edge, 17–47 × 4.0–7.0 μm, narrowly cylindrical to subclavate, septate, with slightly inflated apex. Lamellar trama regular, made up of cylindrical hyphae 7.0–13 µm wide. Pileipellis a cutis made up of cylindrical hyphae 8.0–11 μm broad, with transitions to a trichoderm towards the margin with clavate terminal elements 10–18 μm wide, not pigmented. Stipitipellis a cutis composed of densely arranged, cylindrical hyphae, up to 11 μm wide, slightly constricted at the septa, with acute or tapered end. Clamp connections absent.

Habitat.

Solitary or scattered on soil in mixed coniferous-broad-leaved forest, or on rotten wood, soil, and moss in broadleaved forest.

Distribution.

So far known from eastern China.

Additional specimens examined.

China • Fujian Province, Wuyishan City , 27.7139°N, 117.6533°E, alt. 1113 m, 27 June 2022, collected by Jun-Qing Yan and Bing-Ring Ke, HFJAU 4048 • Zhejiang Province, Lishui City, Suichang County, Huangtakou Village , 28.2679°N, 118.9435°E, alt. 346 m, 12 July 2020, collected by Jun-Qing Yan and Yan-Liu Chen, HFJAU 1907 • Qingtian County, Shigu Lake , 28.2063°N, 120.0415°E, alt. 1130 m, 31 July 2021, collected by Jun-Qing Yan, Bing-Ring Ke, and Zhi-Heng Zeng, HFJAU 2616 • Nanyang Village , 27.9603°N, 120.0020°E, alt. 522 m, 6 August 2021, collected by Yu-Peng Ge and Lan-Yu Sun, HFJAU 2920 .

Notes.

Morphologically, Entoloma orientosinense has much in common with E. albidosimulans G. M. Gates & Noordel. and E. albinellum with regard to the white and collybioid basidiomata. However, E. albidosimulans is distinct by its broader (up to 6 mm), adnate-emarginate lamellae, and belonging to E. subg. Alboleptonia species ( Gates and Noordeloos 2007). Entoloma albinellum differs from new species by its striate pileus, adnexed lamellae, and larger basidiospores (11–12.5 × 7.5–8.5 μm) ( Hesler 1967).

In the molecular data, E. orientosinense fits well within subg. Cyanula , sect. Caesiocincta , subsect. Queletia including E. albinellum and E. queletii . E. queletii is distinguished from new species by the vinaceous-pink pileus and larger basidiospores (10–13 × 6.5–9.0 μm) ( Bas et al. 1988 a).

Figures

Figure 2. E. orientosinense A, B basidiomata A HFJAU 1414, holotype B HFJAU 2616 C basidiospores D cheilocystidia E pileipellis F lamellar trama. All microscopic structures were observed in 5 % KOH, and used 1 % Congo red as the stain except C. Scale bars: 10 mm (A, B); 20 μm (C); 30 μm (D – F).