Micropsalliota vulgaris J. Q. Yan, S. N. Wang, & H. Zeng, 2025

Yan, Jun-Qing, Zeng, Zhi-Heng, Hu, Ya-Ping, Nie, Cheng-Feng, Ke, Bin-Rong, Wang, Sheng-Nan & Zeng, Hui, 2025, Two new species of Micropsalliota (Agaricales, Agaricaceae) from subtropical regions of China, MycoKeys 113, pp. 193-208 : 193-208

Micropsalliota vulgaris J. Q. Yan, S. N. Wang, & H. Zeng sp. nov.

Fig. 3

Etymology.

Name refers to the fact that many known species in this genus share similar macroscopic characteristics with the new species.

Diagnosis.

Micropsalliota vulgaris is mainly characterized by small basidiomata; white to cream pileus, covered with reddish brown to dark brown fibrillose; elongated-ellipsoid to elongated basidiospores in profile view, (6.3) 6.7–8.0 × 3.7–4.4 (4.7) μm; various cheilocystidia; hyphae of fibrils have pale brown vacuolar pigment. It differs from M. squarrosa by having various cheilocystidia.

Holotype.

China • Zhejiang Province, Wencheng County, 24 May 2022, Ya-Ping Hu, Jun-Qing Yan, HFJAU 3350 .

Description.

Pileus 10–35 mm, convex, white to cream, covered with reddish brown to dark brown (9 E 6–9 F 6) fibrillose, dense at the center, sparser towards the edge. Context less than 2.0 mm thick, turning brownish red (9 C 7–9 C 8) in some areas when bruised or cut. Lamellae 3.0–4.0 mm, crowded, free, with 2–3 series of lamellulae, dull white, edge dull white, slightly serrate. Stipe 50–80 mm long, 3.0–4.0 mm thick, cylindrical, slender, white, surface with white fibrils, gradually disappears with aging. Context of stipe turning brownish red (9 C 7–9 C 8) in some areas when bruised or cut. Annulus unobserved.

Basidiospores (6.3) 6.7–8.0 × 3.7–4.4 (4.7) μm, Q = (1.5) 1.6–1.9 (2.0), elongated-ellipsoid to elongated, slightly flattened on one side in profile view, ellipsoid to elongated-ellipsoid in face view, light brown, wall 0.5 μm thick, apically thickened endosporium, without germ pore, inamyloid. Basidia 15–19 × 6.0–7.5 μm, clavate, hyaline, 4 - spored. Pleurocystidia absent. Cheilocystidia 35–62 × 4.2–11 μm, various, tibiiform, capitate, subhypoid, rarely fork, apex capitate, rarely mucronate, 4.0–8.0 μm in diameter. Fibrils composed of hyphae 8.0–15 μm broad, with pale brown vacuolar pigment.

Habit and habitat.

Scattered on soil in broad-leaved forest.

Additional specimens examined.

China • Zhejiang Province, Wencheng County, 25 May 2022, Zhi-Heng Zeng, Shen-Nan Wang, HFJAU 5707 .

Note.

Among the known species of the Micropsalliota , few have a similar combination of characteristics as M. vulgaris , that is, a white pileus covered with brown fibrils, lacks pleurocystidia, and has spores up to 8.0 μm. However, they can be clearly distinguished from M. vulgaris : M. endophaea Heinem. , M. inflata D. D. Ivanova & O. V. Morozova , and M. megaspora R. L. Zhao, Desjardin, Soytong & K. D. Hyde have pilei that are generally less than 10 mm in diameter, and their cheilocystidia are shorter than 40 μm ( Heinemann 1988; Zhao et al. 2010; Ivanova et al. 2023); M. fimbriata T. Gao & Z. W. Ge , and M. gigaspora have clavate cheilocystidia and incrusted hyphae of pileus squamules ( Gao et al. 2024); M. geesterani has a purple pileus that can reach up to 200 mm in diameter ( Parra et al. 2016); M. squarrosa T. Gao & Z. W. Ge has clavate to clavate-capitate cheilocystidia ( Gao et al. 2024); M. ventricocystidiata has ventricose cheilocystidia ( Al-Kharousi et al. 2022).

Figures

Figure 3. Morphological structures of Micropsalliota vulgaris. A – D Basidiomata E spores F basidia G, H hyphae of fibrils I – O cheilocystidia. All microstructures were observed in 5 % KOH, except for G, which were observed in water. Structures of F and I – O were stained by 1 % Congo red. Scale bars: 10 mm (A – D); 10 μm (E – O).