Pholiota songjiangensis E. Tian & C. Lei, 2025

Lei, Chunyu, Deng, Guiyin, Huang, Jiahui, Shen, Yalun, Yan, Wenbo, Tian, Enjing & Fu, Yongping, 2025, New species and newly recorded species of the family Strophariaceae (Agaricomycetes, Agaricales) in China, MycoKeys 124, pp. 309-329 : 309-329

Pholiota songjiangensis E. Tian & C. Lei sp. nov.

Figs 2 , 3

Etymology.

The epithet refers to the location where the holotype specimens were found.

Diagnosis.

Differs from the other Pholiota species by its pallid pileus with appressed and concentric squamules; white stipe covered with light yellowish-brown small scales; ellipsoid to ovoid basidiospores with an obvious germ pore; pleurocystidia as chrysocystidia; cheilocystidia with two shapes: elongate-cylindrical with capitulate apex and narrowly lageniform.

Holotype.

China • Jilin: Jiaohe City, Songjiang County, Shansongling ; elev. 520 m, 43°32'48"N, 127°3'8"E, Caespitose, forming fairy rings around decaying tree stumps and on adjacent ground in broadleaf forests, 5 September 2016, Enjing Tian 37426 ( holotype: HMJAU!) .

Description.

Pileus 8–35 mm in diam, convex, becoming expanded, with a sticky surface when wet, ground color yellowish white (1 A 2), sometimes the central part appears wax white to straw yellow (2 B 3–3 B 4), decorated with concentric, appressed butter yellow to grayish yellow (4 A 5–4 B 5) scales of fibrils agglutinated, the cap margin bears remnants of the veil. Context light gray (1 C 1), sometimes yellowish gray (3 C 2) where stem meets cap. Lamellae attached to slightly running down stem, pallid at first, then cream (4 A 3) to brownish orange (5 C 6), medium broad ( 2–3 mm), L = 44–56, I = 3–7, close, edges even. Stipe 10–45 mm long, 3–7 mm wide, central, cylindrical, solid when young but becoming loosely fibrous in age, surface pale gray (1 B 1) but khaki (4 D 5) near the base. The veil leaving a distinct annular zone on the stipe; above the annulus smooth, below densely covered with chamois (4 C 5) scales.

Basidiospores 5.5–7.5 × 3.5–5 μm, Q = 1.35–1.85, Qm = 1.58 ± 0.25, in face view elliptic to ovate, in side view inequilateral, wall smooth and thick, germ pore obvious, golden brown to linoleum brown (5 D 7–5 E 7) in KOH, slightly paler in Melzer’s reagent. Basidia 17–22 × 6–7 μm, 2 - or 4 - spored, clavate, hyaline in KOH. Pleurocystidia abundant, as chrysocystidia, 23–74 × 7–10 μm, clavate, clavate with a mucronate apex to subfusiform, with an amorphous highly refractive inclusion, hyaline, chamois (4 C 5) to oak brown (5 D 6) in KOH, wall thin and smooth. Cheilocystidia 20–56 × 5–7.5 μm, cylindric with a capitate apex to narrowly lageniform, thin-walled, smooth, content homogeneous, hyaline to milk white (1 A 2) in KOH. Caulocystidia not observed. Gill trama of parallel hyaline hyphae in KOH and with smooth walls, the cells inflated, up to 20 μm in diam. Pileipellis a cutis of oak brown (5 D 6) to chamois (4 C 5) hyphae 3–14 μm in diam, thin-walled, smooth to slightly encrusted. Clamp connections present in all tissues.

Habitat.

Caespitose on stumps and / or on soil in broadleaf forests in summer and fall, often forming fairy rings around decaying tree stumps.

Additional materials examined.

China. • Jilin: Jiaohe City, Songjiang County, Shansongling , clustered at the base of broadleaf tree stumps, 29 August 2020, Hongde Zhai 37427 ( HMJAU) .

Comments.

This species is characterized by a pallid pileus with concentric and appressed butter yellow to wheat scales of agglutinated fibrils, whitish stipe covered with light yellowish-brown small squamules, ellipsoid to ovoid basidiospores with an obvious germ pore, pleurocystidia as chrysocystidia, thin-walled and elongate-cylindrical cheilocystidia with capitulate apex to narrowly lageniform.

Pholiota songjiangensis is similar to Ph. subcaespitosa , especially in terms of its microcharacteristics. However, the latter has a pileus with an umbonate or depressed disc, covered with brownish fibrillose scales that are appressed and often not apparent in age, and a slimmer stipe (40–70 × 2–5 mm) ( Liu et al. 2024), which can be used to distinguish the two species easily. Pholiota caespitosa and Ph. gummosa (Lasch) Singer are also related to Ph. songjiangensis . However, Ph. caespitosa lacks cylindrical cheilocytidia and has lamellae with even edges, whereas Ph. gummosa has no pleurocystidia in the hymenium ( Smith and Hesler 1968).

In the phylogram (Fig. 1 ), Ph. songjiangensis clustered in the Pholiota subgenus Pholiota clade with high statistical support and was sister to Ph. caespitosa and Ph. subcaespitosa but represented a relatively independent lineage. Pholiota songjiangensis differs from Ph. caespitosa by ITS (0.8–1 %) genetic divergence and from Ph. subcaespitosa by ITS (0.3–0.7 %) and 28 S (2–3 sites) genetic divergence. Therefore, Ph. songjiangensis is proposed here as a new Pholiota species belonging to the subgenus Pholiota based on morphological examination and phylogenetic analyses.

Figures

Figure 1. Bayesian inference (BI) phylogram of Agrocybe, Pholiota and Pyrrhulomyces based on dataset (ITS + nrLSU). PPs> 0.95 and bootstrap values > 70 % are shown. Types are indicated in green, and the new species and the species newly recorded in China in this study are in red.

Figure 2. Basidiomata of Pholiota songjiangensis A, B. (HMJAU 37426, holotype). Photos by Enjing Tian. Scale bars: 1 cm.

Figure 3. Microcharacters of Pholiota songjiangensis (HMJAU 37426, holotype). Drawings by Chunyu Lei. A. Basidiospores; B. Basidia; C. Pleurocystidia; D. Cheilocystidia; E. Pileipellis. Scale bars: 10 µm (A – D); 20 µm (E).