Termitomyces nigroalbus C.C. Ao, & S.H. Li, 2025

Ao, Cheng-Ce, Mu, Li-Dan, Luo, Hong-Mei, Tang, Song-Ming, Zhao, Long, Ye, Yang, Luo, Zong-Long & Li, Shu-Hong, 2025, New species of Termitomyces (Agaricales, Lyophyllaceae) from Yunnan Province, China, Phytotaxa 694 (3), pp. 235-246 : 240

Termitomyces nigroalbus C.C. Ao, & S.H. Li , sp. nov. ( Fig. 2 )

Fungal Name number: FN 572206

Etymology:—the epithet ‘nigroalbusʹ refers to the black color of the pileus surface contrasts sharply with the white color of the lamella and stipe.

Holotype:— CHINA. Yunnan Province, Baoshan City , Changning County. 24°54.49’N, 99°40.15’E. 1,958 m, 9 August 2024, collected by Shu-Hong Li ( HKAS 136949 )

Diagnosis: Termitomyces nigroalbus differs from other Termitomyces species by its grayish black, smooth without squamulose on the pileus, stipe grayish white with a few scales, slight bulbous at the base, and whitish pseudorrhiza. Cheilocystidia and Pleurocystidia absent.

Description:— Pileus 4.5–8.5 cm diam, fleshy, conic to convex, convex applanate to plane when mature, radially fibrillose and shiny on the surface, black gray (2F1–2F4) at center, then pale gray (2E2 to 2C2), gradually slightly grayish toward margin, smooth; perforatorium bluntly pointed when mature, black gray (2F1–2F4); margins fimbriate, at first incurved then straight. Lamellae free, 2–4 mm broad, close, white (1A1) when young, becoming pale yellow (1A3) when mature; lamellulae in 1–2 tiers; lamellar edge eroded. Stipe 9.2–12 cm long, 0.6–1.1 cm wide, central, cylindrical, at ground level pale grey (1D2), abundant pale grey squamulose on the surface, fibrous, solid, does swell lightly at the base. Annulus absent. Pseudorrhiza 1.2–3 cm long, 0.3–0.8 cm wide, cylindrical to subcylindrical, tapering downwards; surface white, smooth, longitudinally striate; context solid, fibrous. Spore prints pinkish. No distinctive smell.

Basidiospores (5.02) 5.81–6.94 (7.31) × (3.21) 3.37–4.13 (4.35) µm, L = 6.16, W = 3.80, Q = 1.62, Qm = 1.62±0.13, ovoid to ellipsoid, smooth, thin walled, hyaline. Basidia (14.75) 15.52–21.28 (22.4) × (4.42) 4.65–7.38 (7.77) µm, clavate to slightly flexuose, and two or four sterigmata. Cheilocystidia and Pleurocystidia absent.

Hymenophoral trama 62–82 µm wide, regular, thin walled, hyaline hyphae abundant, 6.5–9.1 µm wide. Hymenial 200–300 µm wide. Pseudorrhiza context of thin-walled, hyaline hyphae, 9.2–12.1 µm wide.

Habitat and distribution: Gregarious on forest soil above the subterranean termitarium. It is currently known only from Yunnan Province, China.

Other material examined: China. Yunnan Province, Baoshan City, Changning County, Ao Chengce 9 August, 2024 (L7169) HKAS136969 ; Li Shuhong 9 August, 2024 (L7170) NKY0204080909 ; same location .

Notes:— Termitomyces nigroalbus is morphologically well distinguished from other known Termitomyces species. The basidiomata are medium-size; piles have an acute process in the middle, black gray, gradually slightly grayish toward the margin; stipe is pale grey, grey squamulose on the surface; the colors are like those of T. pakistanensis , T. intermedius , T. striatus , and T. tigrinus . The pileus of T. nigroalbus has no squamules and is smooth, compared to our specimen (HKAS 136949), T. intermedius broadly conical or convex when seen from aside, dark grey (1F1), often rimose-squamulose in dry condition, squamules easily falling away, and swell slightly at the base ( Tang et al. 2023).

Phylogenetically, T. nigroalbus is a sister to T. schimperi . To clarify the distinctions between these species, T. nigroalbus differs from T. schimperi not only in size but also in other morphological characteristics. While T. schimperi has a pileus 10–15 cm in diameter, ranging in color from ochraceous brown to rust brown and surface alveolately cracked and broken up into thick, featuring pustulate squamules, ochraceous brown to rust brown; T. nigroalbus exhibits Pileus 4.5–8.5 cm diam, black gray (2F1–2F4) at center, then pale gray (2E2 to 2C2), radially fibrillose and shiny on the surface, no squamules; furthermore, the stipe of T. schimperi is 8–14 cm long and 1–3 cm wide, also bearing membranous squamules (remnants of the velar remains), whereas the stipe of T. nigroalbus is 9.2–12 cm long, 0.6–1.1 cm wide, central, cylindrical, at ground level pale grey (1D2), abundant pale grey squamulose on the surface, fibrous, solid, does swell lightly at the base.

Termitomyces nigroalbus was found in Baoshan City.Compared with similar species, the morphological differences and high genetic distance in the clade support T. nigroalbus as a novel species.

Figures

FIGURE 2. Termitomyces nigroalbus. a–b. basidiomata (a. HKAS136949, b. NKY2024080909); c–d. Hymenophoral trama; e–j. basidiospores; k–p. basidia. Scale bars: b = 2 cm; c–d = 20 µm; e–j =2 µm; k–q =10 µm. Photos by: Cheng-Ce Ao.