长白山囊小伞

3.2.1 Cystolepiota changbaishanensis T. Bau and X. Y. Zhou, sp. nov.
MycoBank number: MB 851389 (Figures 3, 4).
Diagnosis: The identifying features of C. changbaishanensis are that the pileus is dirty white to cream, with pulverulent, granulose or subpyramidal squamules, cream, greyish orange, light brown, brown; pileus and pileus context becoming greyish orange to brown after drying; lamellae white to cream, turn grayish orange to light brown when drying; basidiospores obscure small warts visible under SEM; and cheilocystidia lageniform to broadly lageniform.
Etymology: The species epithet “changbaishanensis” is derived from the name of the mountain where the material was collected.
Type: China, Jilin Province, Jiaohe City, Qianjin forest farm, July 23, 2022, coll. T. Bau and H. B. Song (HMJAU68224), Holotype!
Description: Basidiomata small. Pileus 0.8–2.2 cm, hemispherical when young, expanding to plano-convex or applanate, slightly subumbonate with age, dirty white to cream; with pulverulent, granulose or subpyramidal squamules, dirty white to cream, greyish orange (6B2–B8), light brown (7D5–D8), brown (7E5–E8); pileus context whitish, pileus and pileus context becoming greyish orange (6B5–B7) to brown (7E6–E8) after drying. Lamellae free, white to cream, crowded, up to 0.4 cm broad, with 1–3 tiers of lamellulae, turning grayish orange (6B2–B8) to light brown (6D2–D8) when drying. Stipe 3.2–6.2 × 0.1–0.5 cm, subcylindrical, occasionally downward thickened; white to cream on the upper portion, subsmooth, with granulose squamules from the annular area downwards, concolorous with pileus, fragile and fugacious. Annulus white, fugacious. Odor and taste not recorded (Figures 3A–C, 4A).
Basidiospores [150,5,5] 4.6–6.0 (−6.4) × 2.1–3.0 (−3.4) μm, Q = 1.63–2.54, Qv = 2.08, long ellipsoid to cylindrical, hyaline, slightly thick-walled, smooth-walled under the LM, small warts visible under SEM, inamyloid, non-dextrinoid, metachromatic in cresyl blue, cyanophilous. Basidia13–20 × 4–7 μm, clavate, 4-spored, sometimes 2-spored, greyish yellow (4C4–C6). Lamellar trama regular, greyish yellow (4C3–C7). Cheilocystidia 32–56 × 6–12 μm, lageniform to broadly lageniform, greyish yellow (4C4–C7) to golden yellow (1B4–B8), with a long cylindrical-tortuous apex, slightly thick-walled. Pleurocystidia absent. Pileus and stipe covering an irregular epithelium composed of globose, subglobose, spheropedunculate, 10–21 μm in diam., usually 2–5 cells in a string, brownish orange (5C2–C5). Clamp connections present in all structures (Figures 3D–F, 4B–E).
Habitat: Solitary, scattered or clustered on dead leaves and soil of mixed coniferous forests.
Distribution: Found only in Jilin Province, northwestern China.
Additional specimens examined: China, Jilin Province, Helong City, Xianfeng National Forest Park, August 22, 2021, coll. T. Bau and X. Wang (HMJAU68221); Jiaohe City, Qianjin forest farm, July 23, 2022, coll. T. Bau, L. Y. Zhu, W. N. Hou and H. B. Song, (HMJAU68228, HMJAU68229, HMJAU68230); Dunhua City, State forest farm, July 27, 2022, coll. T. Bau and W. N. Hou (HMJAU68225); Baishan City, Jingyu National White Bear Reserve, July 29, 2022, coll. T. Bau and L. Y. Zhu (HMJAU682310); Tonghua City, Baijifeng National Forest Park, July 8, 2023, coll. T. Bau, Q. R. Liu, Z. Q. Cheng, M. Liu and J. L. Wei (HMJAU68226, HMJAU68227, HMJAU68232, HMJAU68222, HMJAU68223).
Notes: Macromorphologically, this species is similar to C. fumosifolia, C. pyramidalis and C. pyramidosquamulosa, because all of them present subpyramidal squamules on the pileus and stipe surface. But the lamellae of Cystolepiota fumosifolia usually have brown spots, and it has pleurocystidia (Vellinga, 2006). Cystolepiota pyramidalis has orange white to pale orange pileus, pale yellow lamellae, which turn brownish orange when touched or mature, and ellipsoid-ovoid basidiospores (Sysouphanthong et al., 2022). The lamellae of Cystolepiota pyramidosquamulosa are yellowish white, do not change color after drying, and do not have cystidia (Qu et al., 2023).
In the phylogenetic trees (Figures 1, 2), Cystolepiota changbaishanensis and C. hetieri are sister clades, but the lamellae of the latter's basidiomata did not change color after drying and exhibited pleurocystidia.