Pluteus cystidiosus (Minnis and Sundb.) Justo, Malysheva & Lebeuf, in Sevcikova et al., Journal of Fungi 9(9, no. 898): 34 (2023)

Qi, Zheng-Xiang, Qian, Ke-Qing, Yue, Lei, Wang, Li-Bo, Guo, Di-Zhe, Wu, Dong-Mei, Gao, Neng, Zhang, Bo & Li, Yu, 2024, New species, new records and common species of Pluteus sect. Celluloderma from northern China, MycoKeys 104, pp. 91-112 : 91

Pluteus cystidiosus (Minnis and Sundb.) Justo, Malysheva & Lebeuf, in Sevcikova et al., Journal of Fungi 9(9, no. 898): 34 (2023)

Figs 2C-D , 4

Pluteus seticeps var. cystidiosus Minnis and Sundberg N. Amer. Fung. 5(1): 13 (2010). Syn.

Description.

Basidiomata medium to large. Pileus 25-41 mm in diam, compressed hemispherical, surface spreading when young, surface with longitudinal vein-like folds from middle to margin when mature, margin mostly transverse folds, light brown to dark brown (5.0YR 5/6-5.0YR 4/12), margin entire. Context dirty white (2.5YR 9/4), odorless, 5-8 mm thick. Lamellae dirty white (2.5YR 9/4), free, dense, thick, unequal, ventricose, 15-18 mm wide. Stipe 30-41 mm long, 12-17 mm wide, cylindrical, slightly thicker at the base, hollow, fibrous, with brown serpentine or crumbly scales on the surface (2.5YR 9/2). Odorless. Spore prints pink.

Basidiospores [200, 10, 2] (-5.0) 5.5-6.0 (-6.5) × (-4.5) 5.0-5.5 μm, avL × avW = 6.0 × 5.0 µm, Q = 1.10-1.20-1.30 μm, avQ = 1.20 μm, spherical, subglobose, slightly pink, smooth, thin-walled, non-dextrinoid, partially containing one droplet or irregular inclusions. Basidia 23-31 × 7-10 μm, clavate, thin-walled, 4-sterigmate, and hyaline in KOH. Pleurocystidia abundant, scattered, 55-102 × 22-36 μm, rod-shaped or subpyriform, vesicular, thin-walled, smooth, and hyaline in KOH. Cheilocystidia abundant, clustered, 37-60 × 15-22 μm, clavate, fusiform or vesicular, thin-walled. Lamellar trama divergent. Pileipellis a hymeniderm or epithelioid hymeniderm, made up of two types of elements; spheropedunculate or pyriform, 27-55 × 24-34 μm; broadly fusiform, inflated-fusiform, lanceolate, narrowly utriform, often mucronate, 56-105 × 11-23 μm; all elements with brown intracellular pigment, often aggregated in spots, slightly thick-walled. Stipitipellis a cutis of cylindrical, hyphae 8-11 μm wide, with pale brown pigment. Caulocystidia common, often in clusters, 36-112 × 9-20 μm, cylindrical, narrowly clavate, narrowly fusiform, spheropedunculate, with brown or yellow-brown pigment. Clamp connections absent in all studied tissues.

Ecology.

Scattered on decaying wood in mixed coniferous forests ( Pinus koraiensis Siebold and Zucc).

Distribution.

Canada, the USA, Japan, Russian Far East.

Additional specimens examined.

China. Heilongjiang Province, Liangshui National Nature Reserve . 47°11'22.24"N, 128°47'89.11"E, 23 June 2019, D.Z. Guo, FJAU 66556 (ITS: OR994068, TEF1-α: PP062825). China. Heilongjiang Province, Liangshui National Nature Reserve. 47°11'22.24"N, 128°47'89.11"E, 28 June 2019, D.Z. Guo, FJAU 66557 (ITS: PP002166, TEF1-α: PP062826) .

Note. Ševcíková et al. (2023) elevated Pluteus seticeps var. cystidiosus to P. cystidiosus based on specimens from the USA, Canada, Japan, and Russia. The present study reports P. cystidiosus as a new record in China. There was almost complete overlap in morphological variation between those reported in the present study and the holotype specimen. Both grow in temperate/cold-temperate forests. However, the basidiospores of the species in the present study were slightly larger, measuring (-5.0) 5.5-6.0 (-6.5) × (-4.5) 5.0-5.5 µm, while those of the holotype specimen were smaller, measuring 4.5-5.5 (-6.2) × 3.5-5.0 µm .

The phylogenetic tree also supports the results of our morphological study, showing that our specimens are clustered in the same branch as those from the USA and Russia, with a support ratio of 1/100.

Figures

Figure 2. Basidiomata features A-B Pluteus brunneodiscus C-D P. cystidiosus E-F P. chrysophlebius G-I P. romellii. Photos by Zheng-xiang Qi (A-B, G-I). Photos by Di-zhe Guo (C-F). Scale bars: 1 cm.

Figure 4. A Macroscopic characteristics of Pluteus cystidiosus B caulocystidia C basidiospores D pleurocystidia E cheilocystidia F basidia G pileipellis. Scale bars: 1 cm (A); 10 µm (B-G).