Pluteus romellii (Britzelm.) Lapl., Dict. iconogr. champ. sup. (Paris): 533 (1894)

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 romellii (Britzelm.) Lapl., Dict. iconogr. champ. sup. (Paris): 533 (1894)

Figs 2G-I , 6

Agaricus romellii Britzelm., Hymenomyceten aus Südbayern VIII: 5 (1891). Syn.

Description.

Basidiomata medium to large. Pileus 20-56 mm broad, compressed hemispherical to spreading, surface with vein-like projections extending to the pileus margin, often with striated dehiscence, with a greasy or almost waxy texture, brown to yellowish-brown (7.5YR 8/8-7.5YR 6/12), margins wavy dehiscence with translucent-striate. Context light yellow (7.5YR 8/12), odorless, 2-3 mm thick. Lamellae yellowish (10.0YR 8/10), free, medium dense, unequal, entire, ventricose, 5-7 mm wide. Stipe 26-41 mm long and 4-8 mm wide, cylindrical, slightly thicker at the base, fibrous, upper part of the stipe white to yellowish (10.0YR 9/8-10.0YR 7/12), smooth, lower part of the stipe with white tomentum, yellow to yellow-brown (10.0YR 8/8-10.0YR 8/12). Odorless. Spore print pale pink.

Basidiospores [120, 4, 2] 7.0-7.5 (-8.0) × 6.0-6.5 µm, avL × avW = 7.0 × 6.0 µm, Q = 1.07-1.25~1.33 µm, avQ = 1.16 µm, globose, subglobose to ellipsoid, transparent to slightly pinkish, smooth, and thin-walled, non-dextrinoid, partially containing one droplet or irregular inclusions. Basidia 27-32 × 8-10 μm, clavate, thin-walled, 4-sterigmate, and hyaline in KOH. Pleurocystidia abundant, scattered, 55-102 × 22-36 μm, rod-shaped or subcylindrical, fusiform, with neck and apical part broader and obtuse, thinly walled, smooth, and hyaline in KOH. Cheliocystidia abundant, clustered, 41-79 × 18-29 μm, pyriform or similarly pleurocystidia shape, thin-walled. Lamellar trama divergent. Pileipellis an euhymeniderm of spheropedunculate and subglobose elements 25-48 × 23-35 μm, with brown or light brown, at the center brown to dark brown. Stipitipellis a cutis, hyphae 6-10 μm wide, hyaline, non-gelatinous, thin-walled. Caulocystidia absent. Clamp connections absent in all tissues.

Ecology.

Solitary to scattered on decaying wood in coniferous forests ( Picea schrenkiana Fisch.).

Distribution.

Europe, Americas, East Asia, Africa.

Additional specimens examined.

China. Xinjiang Uygur Autonomous Region, Ili Kazakh Autonomous Prefecture , Tekes County, Jongkushtai Village , 43°12'26.61"N, 81°91'97.21"E, alt. 2139 m, 10 July 2022, Z.X. Qi, J.J. Hu, and B. Zhang, FJAU 66558 (ITS: OR994057, TEF1-α: PP062827). China. Xinjiang Uygur Autonomous Region, Ili Kazakh Autonomous Prefecture, Tekes County, Jongkushtai Village, 43°15'22.61"N, 81°75'90.21"E, alt. 2147 m, 11 July 2022, Z.X. Qi, J.J. Hu, and B. Zhang, FJAU 66559 (ITS: OR994061, TEF1-α: PP062828) .

Note.

Initially, the description of Pluteus romellii was rather vague ( Britzelmayr 1891), stating that P. romellii was similar to P. nanus (Pers.) P. Kumm, with spores measuring 6-7 μm, and found growing in the soil of Bavaria. It is now widely acknowledged that P. romellii is characterized by a brown pileus, yellow stipe, and the absence of elongated elements in the pileipellis. This species is placed on the phylogenetic tree in subsect. Eucellulodermini under sect. Eucellulodermini Celluloderma ( Orton 1986; Vellinga 1990; Ševcíková et al. 2023). Here, our description of the P. romellii is consistent with the commonly accepted characterization. Phylogenetic analysis shows that it clustered with the epitype (BRNM 761731) with strongly supported (99/0.98).

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 6. A macroscopic characteristics of Pluteus romellii B basidiospores C pleurocystidia D basidia E cheilocystidia F pileipellis. Scale bars: 1 cm (A); 10 µm (B-E); 20 µm (F).