Collybiopsis lignicola R.L. Zhao & W.Q. Yang, 2025

Collybiopsis lignicola R.L. Zhao & W.Q. Yang , sp. nov. Figure 3 View FIGURE 3 .

Fungal name: FN 572125

Diagnosis: The distinctive features include a deep brownish and whitish radially fibrillose pileus, scattered or gregarious on the bark of deciduous trees, broadly ellipsoid to fusiform basidiospores.

Holotype: China, Bejing, Changping District, Dalinggou Village, Kiwi Fruit Valley Scenic Spot , 11 August 2023, Jia-xin Li , Wen-qiang Yang and Ze-zhi Wang , ZRL20233191 ( HMAS 282429 View Materials , GenBank accession-ITS: PQ408934, LSU: PQ408957 ).

Etymology: ‘ lignicola ’ refers to growing from rotten wood.

Macroscopic description:— Pileus 12–24 mm broad, convex to hemispherical when young, becoming planoconvex to flat with an uplifted margin with age, when fresh rich deep brown (6E6-7), surface smooth, radially fibrillose, white (3A2). Lamellae distant, L= 5–11, I = 0.7–1, free, whiteish to yellowish white (3A2). Context thin, white (3A2). Stipe 17–24 × 1.5‒1.9 mm, central to eccentric, cylindrical, tomentose, apex white to yellowish white (3A2), gradually becoming deep downwards (7D2 to 7E6), covered with pubescence. Odor and taste not recorded.

Microscopic description:— Basidiospores 5.1–7.4 × 3.1–4.3 µm, Q = 1.65–1.72, avQ = 1.69, broadly ellipsoid to fusiform, smooth, hyaline, non-dextrinoid, with drops, germ pore absent. Basidia (18.4)20.4–33.6 × (2.1)4.6–9.0 µm, 4-spored, narrowly clavate, colorless, with oil droplets or pigment, sterigmata 1.5–3.5 µm long. Cheilocystidia (18.5)20.1–29.0 × (3.7)4.2–6.5(7.1) µm, utriform to narrowly lageniform, some cylindrical to narrowly clavate, hyaline, with obtuse or sub-capitate apex, base pedunculate or pedicellate, non-gut, well-defined basal clamp. Pleurocystidia 25.5‒28.6 × 4.6‒6.7 µm, clavate, fusiform, hyaline, with obtuse or sub-capitate apex. Caulocystidia absent. Trama hyphae cylindrical, nearly inflated, branched, smooth, non-dextrinoid, 2.4‒5.1 µm wide. Pileipellis cylindrical, smooth, sometimes swollen, thin-walled, 3.1‒5 µm wide hyphae; Stipitipellis cylindrical, parallel along stipe, smooth, sometimes swollen, thin-walled, 1.9‒5 µm wide hyphae. Clamp connections present in all tissues.

Habitat and distribution: Scattered or gregarious on the bark of deciduous trees in summer and autumn.

Additional specimens examined: China, Bejing, Miyun District, Dongshaoqu Township , 9 August 2023, Bin Cao, Min-yu Zhu and Bei Han, ZRL20232668 ; China, Bejing, Changping District, Xixincheng Village, Taoyukou Reservoir , 10 August 2023, Jia-xin Li, Wen-qiang Yang and Ze-zhi Wang, ZRL20233136 .

Notes: Collybiopsis lignicola can be easily distinguished by its deep brownish and whitish radially fibrillose pileus. In the field, C. lignicola appears similar to C. biformis and C. menehune . Collybiopsis biformis differs from this new species by its elongated basidiospores (6.4‒9.2 × 2.4‒4.8 µm) and smaller basidia (<22 µm long) ( Kim et al. 2022). Collybiopsis menehune can be distinguished from C. lignicola by its larger pileus ( 8‒30 mm) and longer basidiospores (7.5‒9.5 × 3.5‒4.2 µm) ( Desjardin et al. 1999; Kim et al. 2022). In the phylogenetic tree ( Fig 1 View FIGURE 1 ), C. dichrous and C. dichroa are sisters to C. lignicola . Morphologically, they can be easily distinguished and C. dichroa has shorter stipe (< 2 cm long) and has reddish-brown color of pileus surface ( Kim et al. 2022). Collybiopsis dichrous has larger basidiospores (8.8–12.8 × 4.0–5.6 µm) and larger basida (29–40 × 6–8 µm) ( Mata et al. 2002).