Minutisphaera aspera Raja, Oberlies, Shearer, A. N. Mill., Mycologia

Minutisphaera aspera Raja, Oberlies, Shearer, A. N. Mill., Mycologia View in CoL 107(4): 855 (2015). FIGURE 3 View FIGURE 3

MycoBank: MB811063

Saprobic on decaying wood, submerged in freshwater habitats. Asexual morph: Undetermined. Sexual morph: Ascomata 91–189 µm, superficial, scattered, dark brown to black, membranous. Ostiole absent. Peridium 2–5 µm wide, comprises two layers, outer layers composed of dark brown cells of textura angularis, inner layer composed hyaline cells of textura prismatica. Hamathecium composed of cellular pseudoparaphyses, sparse in young ascomata, becoming abundant with age, hyaline, septate, filamentous. Asci 59–86 × 27–40 µm (= 70 × 34 µm, n = 20), 8-spored, fissitunicate, obovoid to broadly cylindrical, thick-walled at the apex, lacks an ocular chamber. Ascospores 20–26 × 11–15 µm (= 23 × 14 µm, n = 30), multi-guttulate, bitunicate, ellipsoidal, straight, with a median septum, constrict at the septum, hyaline and thin when young, becoming olive to dark brown and rough-walled at mature, upper and lower cells are equal in length and width, with or without sheath.

Culture characteristics: Ascospores germinating on PDA within 12 h and germ tubes produced from the one end of the spore. Colonies grew on PDA, reaching 18–27 mm in three weeks at 25°C, with dense mycelia, dry, colony edge appears irregularly circular, center is gray velvety with dark brown fuzzy protrusions on the sides, dark brown from reverse.

Material examined:— CHINA, Yunnan Province, Yuxi City, on submerged decaying wood in freshwater stream in Yuanjiang River Basin, February 2022, Hong-Wei Shen, S- 3749 ( KUN-HKAS 135204), living culture, CGMCC 3.27728 = KUNCC 24-17898.

Notes: In phylogenetic analyses, our new collection ( CGMCC 3.27728) clustered with Minutisphaera aspera ( G 427 1a and G 427 1b) with 99% ML and 1.00 PP support ( FIGURE 4 View FIGURE 4 ). Nucleotide comparison showed that our fungal isolate ( CGMCC 3.27728) differs from M. aspera ( G 427 1a) by 9 base pairs out of 538 in the ITS region (1.67%), 1 base pair out of 767 in the LSU region (0.13%), 1 base pair out of 993 in the SSU region (0.10%). Morphologically, our new isolate is similar to M. aspera in having dark brown to black ascomata, obovoid, fissitunicate asci and fusiform to ellipsoidal, hyaline to dark brown, 1-septate, verruculose, guttulate ascospores with similar size (20–26 × 11–15 µm vs. 24–33 × 9–14 µm). Thus, we identify our new collection as M. aspera , a new report for China.