Pholiota subterrestris E. J. Tian & J. H. Huang, 2024

Huang, Jia-hui, Lei, Chun-yu, Shen, Ya-lun & Tian, En-jing, 2024, Two new species of Pholiota (Agaricales, Strophariaceae) from the southwest of China, MycoKeys 109, pp. 171-185 : 171-185

Pholiota subterrestris E. J. Tian & J. H. Huang sp. nov.

Figs 4 , 5

Diagnosis.

Pholiota subterrestris is distinguished from the other species of the genus Pholiota by brownish orange pileus with numerous brown fibrillose scales, pale brown and moderately broad lamellae with even edges, stipe covered with recurved fibrillose scales, evanescent fibrillose annulus; elliptic spores with distinct but small germ pore, fusoid ventricose pleurocystidia with typical amorphous refractive inclusion of chrysocystidia.

Holotype.

China. • Guizhou: Bijie City, Nayong County, Dapingqing National Wetland Park ; elev. 1990 m; 26 ° 41 ' 10 ′′ N, 105 ° 27 ' 30 ′′ E; scattered on soil at base of stump; 22 July 2020; En-jing Tian 37434 (holotype: HMJAU!).

Etymology.

The epithet subterrestris refers to the similarity to Pholiota terrestris .

Description.

Pileus 10–35 mm in diameter, subhemispherical when young, with involute margin, slightly spread when mature, surface slightly viscid when wet, greyish orange to brownish orange (5 B 4–6 C 6), center dark, becoming paler towards the margin, covered with brown (6 E 7) fibrillose scales. Context thick, white to yellowish white (1 A 1–2 A 2), mild odor and taste. Lamellae decurrent to adnate or adnexed, moderately broad, close, L = 39–44, I = 3–7, pale yellow to light brown (4 A 3–5 D 6), edges even. Stipe 18–30 mm long, 4–7 mm thick, central, equal, solid, brownish orange (5 C 4) above, brown (6 E 5) below, covered with light brown (6 D 6) fibrillose squamulose, often compressed at the base

Basidiospores 5.4–6.1 × 3.6–4.2 µm, Q = 1.30–1.56, Q m = 1.47, smooth, in face view broadly elliptic to elliptic, in profile a little bean-shaped, apical pore distinct but small, containing oil-bearing droplet or irregular inclusions, greyish yellow (4 B 5) in KOH and light yellow (4 A 5) in Melzer’s reagent. Basidia 17.1–21.8 (– 24.0) × 5.0–6.3 µm, 4 - spored, clavate, hyaline in KOH, pale yellow (4 A 3) in Melzer’s reagent. Pleurocystidia of two types: 1) 33.3–46.7 × 5.5–9.5 µm, subclavate to fusoid ventricose with a subacute apex, wall thin and smooth, content homogeneous, blond to dark yellow (4 C 4–4 C 8) to hyaline in KOH; 2) chrysocystidia, 34.2–58 × 8.3–10.4 µm, fusoid to fusoid-ventricose, the neck often drawn out to a crooked filamentose projection with a subacute apex (up to 19.6 µm long), walls thin, smooth, with a refractive-amorphous inclusion, hyaline in KOH. Cheilocystidia abundant, (20.0 –) 22.9–39.2 (– 48.3) × 3.9–12.7 µm, clavate to clavate-capitate, wall thin, at times somewhat thickened in apex (about 1 µm), hyaline in KOH. Caulocystidia none observed. Gill trama of parallel hyphae, the cells inflated up to 27.5 µm, thin-walled, smooth, hyaline in KOH. Pileipellis hyphae hyaline to light brown (6 D 7), 3.7–10 µm diam., with encrusted walls. Content hyphae hyaline, 10–37.5 (– 50) µm diam., cells inflated, smooth and thin-walled. Clamp connections present in all the tissues.

Habitat.

Scattered or gregarious on soil at the base of a stump or on buried wood in summer.

Additional materials examined.

China. • Guizhou: Bijie City, Qixingguan District, Baima Mountain , gregarious on soil or on buried wood, 15 August 2022, Guang-cheng Cao 37435 ( HMJAU) .

Discussion.

This species is characterized by a brownish orange pileus with numerous brown fibrillose scales, pale brown lamellae with even edges, a stipe covered with recurved fibrillose scales, an evanescent fibrillose annulus, elliptic spores with a distinct but small germ pore, and fusoid ventricose pleurocystidia with typical amorphous refractive inclusions of chrysocystidia.

Pholiota subterrestris is similar to P. terrestris Overh. , especially in terms of micro-characteristics, such as pleurocystidia, cheilocystidia, and basidiospores. However, it is easy to differentiate between the two species based on the macro characteristics. P. terrestris has a larger pileus (20–80 mm broad) without an orange tone, narrow and crowded lamellae with uneven edges, and a longer stipe (30–80 mm long) ( Smith and Hesler 1968). Furthermore, in habitat, P. terrestris is caespitose on soil, whereas P. subterrestris is scattered or gregarious. Phylogenetic analyses showed that P. subterrestris was sister to P. terrestris in the Subgenus Pholiota clade (Fig. 1 ), which also indicated a close relationship between the two species.

Figures

Figure 1. BI phylogram of Pholiota based on the dataset (ITS + 28 S). PPs > 0.95 and bootstrap values > 70 % are shown. Types are indicated in green, and the new species from China in this study are in red.

Figure 4. Basidiomata of Pholiota subterrestris (HMJAU 37434, holotype). Photo by En-jing Tian. Scale bar: 1 cm.

Figure 5. Microcharacters of Pholiota subterrestris (HMJAU 37434, holotype). Drawings by Jia-hui Huang A basidiocarps B basidia C basidiospores D pleurocystidia E cheilocystidia F pileipellis. Scale bars: 1 cm (A); 5 µm (C); 10 µm (B, D, E); 20 µm (F).