Lepiota baiyunensis Y.S. Liang & L.H. Qiu, 2023

Liang, Ying-Shan, Xu, Yi-Wen, Ouyang, Min, Huang, Xiao-Xia, Lin, Zhi-Jun & Qiu, Li-Hong, 2023, Lepiota baiyunensis sp. nov. (Agaricales, Agaricaceae) from Baiyun Mountain, China, Phytotaxa 606 (1), pp. 1-15 : 8-9

Lepiota baiyunensis Y.S. Liang & L.H. Qiu , sp. nov. ( Figs 3 & 4 )

MycoBank: MB 848014

Diagnosis:— Lepiota baiyunensis sp. nov. differs from L. lilacea by light yellow lamellae, stipe covered with lamellar squamules, lacking true annulus, usually clavate cheilocystidia and trichodermal pileus covering with long, cylindrical elements.

Holotype:— CHINA. Guangdong Province: Guangzhou City, Baiyun Mountain , 23°11′37″N 113°18′49″E, alt. 49m, 27 May 2022, X.X. Huang, B22052705 (holotype! GDGM 91089 ).

Etymology:—the epithet ‘‘ baiyunensis’’ refers to the type location, Baiyun Mountain, Guangzhou, China.

Description:—Basidiomata small to medium size. Pileus 8–37 mm in diam., initially hemispherical, then convex, later expanding to plano-convex or applanate with a slightly umbonate top; margin slightly incurved when youth, then plane, with a little remnant of universal veil; background yellowish (7.5Y9/4) to off-white (10Y9/2) covered with tawny (7.5YR4/8) to brown (5YR2/6), slightly recurved aggregated fibrillose scales, denser at disc, paler and sparser toward the margin, becoming appressed and lessened with aging; surface dull and dry. Lamellae free, light yellow (7.5Y9/4), thin, close, ventricose, with intercalated lamellulae, 0.6–2 mm broad. Stipe 8–22 × 2–4 mm, cylindrical to subclavate to cylindrical with age, mildly tapering at the apical part and swelling at base, with rhizomorphs; surface above annular zone, off-white (10Y9/2) to pale yellow (10Y9/4), glabrous; below annular zone, yellowish (7.5Y9/2) to pale brown (10YR5/8), covered by irregular lamellar squamules which edge concolorous with the fibrils on pileus, the remaining white (10Y9/2), gradually squamules becoming appressed and less conspicuous in age. Context off-white (10Y9/2), flesh in pileus and hollow in stipe, changing indistinctively on handing. Lacking of real annulus, only a micro ring made up of floccose fibrils at annular zone, white (10Y9/2), evanescent, disappearing in age. Odor mushroom like.

Basidiospores [100/3/2] (3.8–)3.9–5.1(–6.0) × (1.7–)1.9–2.8(–3.2) μm, avl × avw = 4.48 × 2.40 μm, Q = 1.53– 2.43, Qav = 1.89 ± 0.20, narrowly ellipsoid to ellipsoid, smooth with a prominent apiculus, yellowish-brown (5Y7/4) or hyaline in KOH, brown to reddish brown in Melzer’s regent, dextrinoid and non-metachromatic in Cresyl Blue. Basidia [60/2/2] (9.0–)11.0–15.2(–16.2) × (3.8–)4.1–6.1(–6.2) μm, avl × avw = 12.65 × 5.05 μm, narrowly clavate to clavate to broadly clavate, 4-spored in mass, rarely 1- or 2-spored, hyaline to very pale yellow (7.5Y8/2) in KOH. Pleurocystidia absent. Cheilocystidia (8.7–)9.6–18.5(–24.5) × (3.5–)4.0–7.9(–8.1) μm, mostly clavate, sometimes narrowly clavate to subcylindrical, rarely narrowly pyriform, often septate with long cylindrical basal cell, hyaline to very pale yellow (7.5Y8/2) in KOH. Pileus covering a trichoderm, made up only of long, cylindrical hyphae and somewhat flexuous, terminal element 2.5–6.0 μm broad, often with an obtuse apex, hyaline or yellowish (7.5Y8/4) in KOH. Stipitipellis a cutis, 0.5–2.8 µm broad, composed of narrowly cylindrical hyphae, similar to pileus covering but arranged closed, yellowish (7.5Y8/4) in KOH. Clamp connections present in all parts of basidiomata.

Habitat:—Gregarious or scattered on monsoon evergreen forest soil mixed with rotted leaves.

Other specimens examined:— CHINA. Guangdong Province: Guangzhou, Baiyun Mountain , 23°11′21″N 113°18′38″E, alt. 57m, 5 May 2018, L.H. Qiu, B18050516 ( GDGM 91088 ); 23°10′57″N 113°18′23″E, alt. 108m, 27 May 2022, Y.S. Liang, B22052708 ( GDGM 91090 ) .

Figures

FIGURE 3. Lepiota baiyunensis sp. nov.: a–h. fresh basidiomata (a. B18050516; b–c. B22052705, holotype; d-h. B22052708); i. Scanning electronic micrographs of basidiospores; Scale bars: a–h = 10 mm; i = 1 μm. Photos by X.X. Huang and Z.J. Lin.

FIGURE 4. Lepiota baiyunensis sp. nov. (B22052705, holotype). a. Basidiospores; b. Pileus covering; c. Stipitipellis; d–f. Basidia; g–i. Cheilocystidia. Scale bars a–b, d–i = 10 μm; e = 20 μm. Photos by Y.S. Liang.