Thaxterogaster sinoscaurus M.L. Xie, T.Z. Wei & C.T. Li, 2024

Thaxterogaster sinoscaurus M.L. Xie, T.Z. Wei & C.T. Li , sp. nov., Fig. 2 View FIGURE 2

Fungal Names FN572110

Diagnosis:—Similar to other species in Thaxterogaster sect. Scauri , but differ in its olive brown to yellowish or orange tinge pileus, rather bigger basidiospores. The ITS sequences of the new species are distinct from other members of the sect. Scauri and deviating from them by at least 17 substitutions and indel positions.

Etymology:—The name refers to the new species’ affinity to T. scaurus and the type location, China. Holotype:— CHINA. Anhui Province, Lu’an City, Jinzhai County, Tiantangzhai, in mixed forest with Pinus and Quercus trees, 22 September 2023, 31°6′51″ N, 115°46′29″ E, alt. 1500 m, Meng-Le Xie, HMJAU58993. Description:—Pileus 5.5–8 cm in diam., convex to expanded, with a shallow umbo, viscid, very finely innately fibrillose, center olive brown (4D6), later pale yellow (3A3), grayish yellow (4C5), or brownish orange (6C6), margin olive (3E3-3E5), with strongly hygrophanous streaks at the margin when moist. Lamellae emarginate, up to 6.5 mm wide, moderately crowded, olive (2E4-2E8), olive brown (4D4-4D8) to yellowish brown (5D5-5E7). Stipe 5.5–8 cm long, 1.1–1.7 cm thick at apex, with a marginate bulb at the base, 2.5–3.5 cm wide, surface pale green (29A3) to brown (7C7-7E8), covered with green (28A6-28A8) universal veil remnants, pale blue tinge on apex, basal mycelium with greenish white to light green (28A2-28A4), later almost white (-A1), somewhat hollow. Context in pileus thick, up to 11 mm at the center, whitish (-A1), yellowish (3A4-3B6) near the surface, with a light blue tinge (20A2-20C3) near the lamellae, watery brown (6D5-6E8) when moist, in the upper part of the stipe watery blue (20A6), downwards whitish (-A1), to yellowish (3A4-3B6), bluish tinge (20A2) in the bulb base, later white to yellowish (-A1-2A2). Odor weakly, taste mild.

Basidiospores 10.0–12.5 (14.2) × 6.2–7.8 (8.5) µm, Q = 1.41–1.87, X av. = 11.1–11.4 × 7.0–7.3 µm, Q av. = 1.52– 1.63, ellipsoid to oblong, moderately to fairly strongly, and densely verrucose. Basidia 29–38 × 9–13 µm, 4-spored, clavate, almost colorless in 5% KOH. Lamellar edges fertile. Cystidia absent. Pileipellis: epicutis about 110–130 µm thick, gelatinous, hyphae 2.8–7.2 µm wide, upper part colorless, lower part light brownish in 5% KOH, smooth. Hypodermium present, hyphae 11–25 µm wide, subcellular, yellowish in 5% KOH. Clamp connections present.

Ecology and distribution:—In mixed forests with Pinus and Quercus trees. Known from Anhui and Jilin provinces of China.

Additional specimens examined:— CHINA. Anhui Province, Lu’an City, Jinzhai County, Dabie Mountains, Tiantangzhai, in mixed forest with Pinus and Quercus trees, 22 September 2023, 31°7′1″ N, 115°46′37″ E, alt. 1470 m, Meng-Le Xie, HMJAU58994; 31°7′20″ N, 115°46′49″ E, alt. 1360m, Meng-Le Xie, HMJAU58995. Jilin Province, Yanbian Chaoxianzu (Korean) Autonomous Prefecture, Yanji County, Sandaowan Town, in Quercus mongolica dominant forest with a few Pinus saplings, 23 September 2020, 43°16′17″ N, 129°6′31″ E, alt. 620 m, Meng-Le Xie, HMJAU58992.