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

Figs 8 h – i , 9

Etymology.

The specific epithet “ constrictospora ” means the constricted ellipsoid shape of basidiospores.

Diagnosis.

Pileus sordid yellow to cinnamon with grayish hue when young, orange-brown to chestnut-color at center, brown-gray to gray at margin when age; fine sulcate-striate up to center; context thin, pale gray to gray; basidiospores 10.7–11.4 × 8.8–9.1 × 6.4–6.9 μm, broad ellipsoid to ellipsoid, usually constricted in middle part, dark red-brown to almost black, germ pore central; basidia dimorphic; cheilocystidia globose, subglobose, utriform, ellipsoid or broad lageniform; pleurocystidia similar to cheilocystidia; sclerocystidia present.

Type.

CHINA • Jiangsu Province, Nanjing City, North Garden of Nanjing Botanical Garden Mem. Sun Yat-sen , 32°05'55"N, 118°83'61"E, 207 m a. s. l., August 28 th 2021, H. T. Luo, LHT 01 (holotype HMJAU 60336 ) .

Description.

Pileus 8–12 × 5–10 mm when still closed, 12–19 mm when mature, at first conical to convex, finally become flat, with glabrous disc at center, sometimes slightly depresses; dry; sordid yellow to cinnamon with grayish hue when young, orange-brown to chestnut-color at center, brown-gray to gray at margin when aged; fine sulcate-striate up to center. Context thin, pale gray to gray, odor and taste not distinctive. Lamellae crowded, almost free to free, 1–2 mm in wide, L = 30–41, I = 0 or 1, initially pale gray then become gray to dark gray when mature, more pale at margin; hardly deliquescent. Stipe 49–61 × 2–3 mm, cylindrical, hollow, almost equal, pale gray and with somewhat brown hue at base, subglabrous with sparse tiny hairs, clavate. Spore print without recording.

Basidiospores [42, 3, 2] (9.6 –) 10.7–11.4 (– 13.2) × (7.6 –) 8.8–9.1 (– 9.8) × (6.1 –) 6.4–6.9 (– 7.5) μm, Q 1 = 1.07–1.42, Q 2 = 1.36–1.59, av. Q 1 = 1.24, av. Q 2 = 1.47; broad ellipsoid to ellipsoid, or mitriform, usually constricted in middle part, with apical papilla and convex base in front view, slightly flattened, ellipsoid in side view; smooth, dark red-brown to almost black; inamyloid; germ pore central, 2.5–3.1 μm wide. Basidia dimorphic, 20–32 × 11–12 μm, sterigma 3–6 μm in length, clavate, hyaline, 4 - or 2 - spored, surrounded with 4–6 pseudoparaphyses; subhymenium composed of ellipsoid, oblong or cylindrical elements, 18–28 × 10–18 μm. Cheilocystidia 20–70 × 11–26 μm, globose, subglobose, utriform, ellipsoid or broad lageniform, smooth, colorless, thin-walled. Pleurocystidia 15–60 × 11–25 μm, similar to cheilocystidia. Lamella trama regular, 3–13 μm in diam, hyaline, colorless, thin-walled. Pileipellis a hymeniderm at yellow-brown sulcate, made up of sphaeropedunculate cells, 19–43 × 11–21 μm, hyaline, with brown hue at base in most cases; other part of pileus with brown-gray hue a cutis, made up of hyaline, brown to brown-gray, 3–8 μm in diam; pileus trama hyphae densely interwoven, thin-walled, hyaline, yellow-brown to brown, 4–17 μm wide; sclerocystidia 29–161 × 6–9 μm, yellow-brown, thick-walled, wall 1.4–2.8 μm in thickness. Caulopellis hyphae parallel, 4–9 μm wide, hyaline, thin-walled, sometimes diverticulate; caulocystidia unseen, however, clustered tiny hairs at stipe pellis; hyphae of stipe trama 9–21 μm wide, colorless, thin-walled. Clamp connection present at all tissues.

Ecology.

Solitary, subfasciculate, or in small groups, grow on wood chips. Fruiting in August. Only known from type locality.

Other specimens examined.

CHINA • Jiangsu Province, Nanjing City, North Garden of Nanjing Botanical Garden Mem. Sun Yat-sen , 32°05'55"N, 118°83'61"E, 207 m a. s. l., August 28 th 2021, W. J. Li, HMJAU 60338 (LWJ 03) .

Note.

Differed from other species with sclerocystidia, Parasola constrictospora has distinct brown pileus, constricted ellipsoid basidiospores and lignicolous habitat. The sparse tiny hairs on stipitipellis might be the veil residue. This species may also distribute in Pakistan based on phylogenetic results (in Figs 1 – 4 Parasola aff. auricoma LAH-SHP- 7 and Parasola aff. auricoma LAH-SHP- 11).

Figures

Figure 1. Phylogeny inferred from four-locus dataset (ITS + LSU + tef 1 - α + β-tublin), with branch lengths based on the Maximum Likelihood analysis. Only BS over 50 % and BPP over 0.90 are given in the tree. Eight newly described species and three new records to China are indicated in red and blue bold letters respectively. The blue, green and yellow background indicates sect. Conopileae, transitional taxa and typical taxa of sect. Parasola respectively. The two sections are displayed on the right of the phylogram.

Figure 4. Phylogeny inferred from ITS + LSU dataset, with branch lengths based on the Maximum Likelihood analysis. Only BS over 50 % and BPP over 0.90 are given in the tree. Eight newly described species and three new records to China are indicated in red and blue bold letters respectively.

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 9. Basidiomata and microscopic structures of P. constrictospora: a basidiomata (HMJAU 60336, HMJAU 60337); b pileipellis (HMJAU 60336); c basidiospores (HMJAU 60336, HMJAU 60337); d basidia (HMJAU 60336); e cheilocystidia (HMJAU 60336); f pleurocystidia (HMJAU 60336); g stipitipellis (HMJAU 60336). Scale bars: 1 cm (a); 10 μm (b – g).