Cystolepiota flavolamellata Salichanh, Sysouph., & Luangharn

Salichanh, Thaviphone, Sysouphanthong, Phongeun, Thongklang, Naritsada & Luangharn, Thatsanee, 2024, Cystolepiota flavolamellata (Verrucosporaceae, Agaricales), a new species from Southeast Asia, Phytotaxa 645 (1), pp. 18-28 : 24

Cystolepiota flavolamellata Salichanh, Sysouph., & Luangharn sp. nov. ( Figs. 3 , 4 )

Index Fungorum number: IF 900754; Facesoffungi number: FoF14507

Etymology:—(Latin) flavus= yellow, and lamellata= gill, the name refers to its yellowish gills.

Holotype:— THAILAND. Chiang Rai Province, Muang District, Mae Fah Luang University , 18 June 2022, 20°02’43.04′′N, 99°53’53.02′′E, 457 m, T. Salichanh TS99, MFLU 23-0138 .

Diagnosis:— Cystolepiota flavolamellata is recognized by the combination of the following characteristics: small basidiomata, large pyramidal squamules on pileus and stipe, pileus covering an epithelium, with light brown to brown granules, yellowish white to pale yellow lamellae, ellipsoid to oblong ovoid or amygdaliform basidiospores, various cheilocystidia shapes, a white fibrillose stipe, and the presence of clamp connections.

Description:— Pileus 5–12 mm diam., subglobose to hemispherical or convex, expanding to parabolic or campanulate, with or without umbo, with incurved margin, granulose to powdery when young, light brown to brown (7D5–8), then breaking up into concolorous granules or warts, with irregular pyramidal squamules when mature, on a white to orange-white (5A2) background; margin with concolorous granules or squamules with cortinate and orange-white (5A2) remnants; context white, up to 1 mm thick. Lamellae free, up to 1.2 mm in depth, yellowish white to light yellow (4A2–4), with a concolorous eroded edge, becoming light brown to brown (6D5–8) when mature or bruised, soft, close, with 2 tiers of lamellulae. Stipe 15–27 × 2–2.5 mm, centrally attached, cylindrical, with white fibrils from apex to annular zone, towards the base covered with squamules concolorous with the pileus, on white to orange-white (5A2) background, turning light brown to brown (6D5–8) when mature or bruised; context hollow, white to orange white (5A2), turning light brown to brown (6D5–8). Spore print white. Odour not observed.

Basidiospores 2.8–4.5 × 1.6–2.6 µm, x̅ = 3.4 × 2.2 µm, Q = 1.2–2.0, Qav =1.56, broadly ellipsoid to oblong-amygdaliform to ovoid in lateral view, broadly ellipsoid to oblong in frontal view, hyaline, slightly thick-walled, non-dextrinoid and non-amyloid. Basidia 15–19 × 2.7–5.0 µm, four-spored, narrowly clavate to clavate, thin-walled, hyaline, clamped at base. Pleurocystidia absent. Cheilocystidia 20–66 × 3.5–13.6 µm, variable in shape, oblong, shortclavate to clavate, narrowly conical to narrowly utriform or utriform, narrowly fusiform to fusiform, often clavate with appendicular apex, hyaline, clamped at base. Pileus covering an irregular epithelium made of globose to subglobose elements, globose elements 8–45 µm diam., subglobose elements 12–45 × 13.8–40.5 µm, thin-walled, and with light brown intracellular and parietal pigments. Stipe covering an irregular epithelium similar to that of the pileus. Clamp connections present in all tissues.

Habitat and distribution:—Growing in small groups, saprotrophic on humus-rich soil of mixed deciduous forest with Ficus spp . in Thailand and mixed forest dominated by Lithocarpus spp . and Castanopsis spp . in Laos.

Additional material examined:— Laos, Oudomxay Province, Xay District, Houay Houm village, 6 September 2014, Sysouphanthong P, PS2014-993 ( HNL502664 ) .

Figures

FIGURE 3. Basidiomata of Cystolepiota flavolamellata. a–d Collection from Thailand (MFLU 23-0138, holotype). e–f Collection from Laos (HNL502664). Scale bar: a–f = 10 mm. Photos: a–d by Thaviphone Salichanh, e–f by Phongeun Sysouphanthong.

FIGURE 4.Microcharacters ofCystolepiota flavolamellata(MFLU 23-0138,holotype).a=Elements onpileus covering.b =Basidiospores. c = Basidia. d = Cheilocystidia. Scale bars: a = 20 µm, b = 5 µm, d–c =10 µm. Drawing by: Thaviphone Salichanh.