Parasola grisella T. Bau & L. Y. Zhu, 2025

Zhu, LiYang & Bau, Tolgor, 2025, Emendation of morphology and infrageneric standards of Parasola (Psathyrellaceae, Agaricales) and its species diversity in China, IMA Fungus 16, pp. e 143796-e 143796 : e143796-

Parasola grisella T. Bau & L. Y. Zhu sp. nov.

Figs 8 d – g , 10

Diagnosis.

Basidiomata relatively large. Pileus pearly white to pale gray at margin and yellow-brown at the center; with annular zone at the junction of the lamellae and stipe, basidiospores 9.3–10.1 × 7.7–8.0 × 6.3–6.5 μm, broad ellipsoid in front view, brown to dark brown; basidia dimorphic, 4 - spored; cheilocystidia 19–77 × 8–19 μm, subglobose, utriform, ellipsoid or broad lageniform; pleurocystidia 55–80 × 19–25 μm, (sub) cylindrical or lageniform; pileipellis a hymeniderm mixed with sphaeropedunculate and clavate cells; sclerocystidia present; clustered tiny hairs at stipipellis.

Etymology.

The specific epithet “ grisella ” refers the distinct pearly gray color of pileus when mature.

Type.

CHINA • Anhui Province, Chizhou City, Shitai County, Guniujiang National Nature Reserve , 30°01'39"N, 117°52'89"E, 164 m a. s. l., June 15 th 2022, L. Y. Zhu, H. B. Song and H. Cheng, Z 22061506 ( HMJAU 60338 , holotype) .

Description.

Basidiomata small to medium-sized. Pileus 5–9 × 5–8 mm when still closed, 14–27 mm when mature, at first conical to subglobose, finally become flat, with glabrous disc at center; dry; yellow brown to red brown at first, then fade from edge of pileus, finally become pearly gray except sordid yellow to yellow brown at center; fine sulcate-striate up to center. Context thin, cream to pale gray, odor and taste not distinctive. Lamellae crowded, free, with annular zone at the junction of the lamellae and stipe, 1–2 mm in wide, L = 35–43, I = 0–2, initially pale gray then become gray with olive-green hue, dark gray when mature, more pale at margin; hardly deliquescent. Stipe 43–64 × 2–3 mm, cylindrical, hollow, almost equal, cream to pale gray, subglabrous with sparse tiny hairs, clavate. Spore print not recorded.

Basidiospores [63, 5, 3] (7.7 –) 9.3–10.1 (– 10.5) × (6.8 –) 7.7–8.0 (– 8.4) × (5.8 –) 6.3–6.5 (– 6.7) μm, Q 1 = 1.18–1.28, Q 2 = 1.26–1.56, av. Q 1 = 1.21, av. Q 2 = 1.40; broad ellipsoid, occasionally with 5 - or 6 - rounded angles, with apical papilla and convex base in front view, slightly flattened, narrow ellipsoid to ellipsoid in side view; smooth, brown to dark brown in H 2 O and olive-brown in 5 % KOH; inamyloid; germ pore central, 1.7–2.7 μm wide. Basidia bimorphic, 17–32 × 8–11 μm, sterigma 3–6 μm in length, clavate, sometimes constricted in middle part, hyaline, 4 - spored, surrounded with 3–5 pseudoparaphyses; subhymenium composed of ellipsoid, oblong or cylindrical elements, 7–20 × 8–11 μm. Cheilocystidia 19–77 × 8–19 μm, subglobose, utriform, ellipsoid or broad lageniform, smooth, colorless, thin-walled. Pleurocystidia 55–80 × 19–25 μm, (sub) cylindrical or lageniform. Lamellar trama regular, 8–16 μm in diam, hyaline, colorless, thin-walled. Pileipellis a hymeniderm at sulcate, made up of sphaeropedunculate and clavate cells, 29–43 × 9–22 μm, hyaline, with brown hue at base in most cases; other part of pileus a cutis, made up of hyaline, colorless or slightly yellow hyphae, 3–8 μm in diam; pileus trama hyphae densely interwoven, thin-walled, hyaline, yellow-brown to brown, 6–17 μm wide; sclerocystidia 29–181 × 5–11 μm, yellow-brown, thick-walled, wall 2.5–3.2 μm in thickness. Stipitipellis hyphae parallel, 4–10 μm wide, hyaline, thin-walled, sometimes diverticulate; caulocystidia unseen, while clustered terminal cells of the stipitipellis protrude from the surface; hyphae of stipe trama 9–16 μm wide, colorless, thin-walled. Clamp connections present.

Ecology.

Subfasciculate or in small groups, grow on clayey soil, humus layer or adnate to trumps in broad-leaved tree with Liriodendron chinense , Liquidambar formosana , Osmanthus fragrans and Camphora officinarum . Fruiting in May to July. Known from East and Central China regions.

Other specimens examined.

CHINA • Same location with holotype, June 15 th 2022, L. Y. Zhu, H. B. Song and H. Cheng, HMJAU 64098 (Z 22061508) ; CHINA • Jiangsu Province, Nanjing City, North Garden of Nanjing Botanical Garden Mem. Sun Yat-sen , 32°05'55"N, 118°83'61"E, 191 m a. s. l., May 16 th 2021, Z. H. Zhang, HMJAU 64097 (ZZH 516) ; CHINA • Hubei Province, Wuhan City, lawn beside Art College of Wuhan University, No. 421 Luojiashan Road , 30°32'27"N, 114°21'45"E, 39 m a. s. l., May 29 th 2022, M. H. Tang, HMJAU 60093 (355) ; CHINA • Hubei Province, Wuhan City, Lover Slope of Wuhan University , 30°32'27"N, 114°21'31"E, 51 m a. s. l., June 2 nd 2022, M. H. Tang, HMJAU 60094 (390) ; CHINA • Hunan Province, Changsha City, Yuelu Mountain , 28°11'01"N, 112°55'59"E, 218 m a. s. l., July 8 th 2022, L. Y. Zhu, H. B. Song and H. Cheng, HMJAU 60095 (Z 22070833) .

Note.

This species is a sister to Parasola auricoma , which differs from the former in having a yellowish-brown pileus at maturity, ellipsoid to elongated ellipsoid basidiospores in frontal view (Q 1 = 1.35–2.05), and sclerocystidia with wall thickness of 0.9–1.4 μm (Uljé 2005; Huang 2019). Geographically, the known distribution range of Parasola grisella is the middle and lower reaches of the Yangtze River in China, which belongs to the subtropical region, while the suitable habitat of Parasola auricoma is concentrated in the northern temperate zones of Asia and Europe.

Parasola grisella is macroscopically similar to Parasola setulosa (Berk. & Broome) Redhead, Vilgalys & Hopple , as both species exhibit grayish-white pilei at maturity. However, the latter is usually solitary, lacks an annular zone at the junction of the lamellae and stipe, has ellipsoid basidiospores in frontal view, lageniform or clavate cheilocystidia, and sclerocystidia with wall thickness of 2.8–4.4 μm ( Cho et al. 2018; Huang Mei 2019). Additionally, Parasola constrictospora , which is also distributed in the middle and lower reaches of the Yangtze River, differs from this species by its constricted basidiospores in front view.

Figures

Figure 8. Basidiomata of species with sclerocystidia in sect. Parasola: a – c Parasola auricoma: a, b HMJAU 64094, c HMJAU 46369; d – g Parasola grisella: d HMJAU 64097, e HMJAU 64098, f HMJAU 60094, g HMJAU 60095; h – i Parasola constrictospora: h HMJAU 60336, i HMJAU 60337; j – l Parasola setulosa: j, k HMJAU 60096, l HMJAU 60097; m – o Parasola malakandensis: m HMJAU 60360, n HMJAU 64091, o HMJAU 64090.

Figure 10. Basidiomata and microscopic structures of Parasola grisella: a basidiomata (HMJAU 60338, HMJAU 64098, HMJAU 60095); b pileipellis (HMJAU 60338); c basidiospores (HMJAU 60338, HMJAU 64097, HMJAU 64095, HMJAU 60095, HMJAU 60093); d basidia (HMJAU 60338); e cheilocystidia (HMJAU 60338, HMJAU 64097); f pleurocystidia (HMJAU 60338, HMJAU 64097); g stipitipellis (HMJAU 60338, HMJAU 64097). Scale bars: 1 cm (a); 10 μm (b – g).