Pseudodiatrype hainanensis S. H. Long & Q.R. Li, sp. nov.

MycoBank number: MB 839659; Index Fungorum number: IF 839659; Facesoffungi number: FoF12725; Fig. 3

Holotype. GMB0054.

Etymology. Refers to the location of collections, Hainan Province.

Description. Saprobic on decaying branches of an unidentified plant. Sexual morph: Stromata wart-like, pustulate, 2–3.6 mm long and 1.6–3 mm broad (av. = 3.2 × 1.9 mm, n = 30), about 2 mm thick, 5–20 in single stroma, visible as black, rounded to irregular in shape on the host surface, erumpent through host bark, solitary to gregarious. Endostroma composed of an outer layer of dark brown to black, small, tightly packed, thin parenchymatous cells and an inner layer of white, large, loose parenchymal cells with powdery, thin, yellowish tissue. Ostiole opening separately, papillate or apapillate, central. Perithecium immersed in the stroma, globose to subglobose, glabrous, with cylindrical neck, brevicollous or longicollous, 193–347 μm high, 138– 206 μm diam. (av. = 278 × 156 μm, n = 10). Peridium 30–50 μm thick, dark brown to hyaline with textura angularis cell layers. Asci 110–155.5 × 6–10 μm (av. = 132 × 8 μm, n = 30), 8-spored, unitunicate, clavate, long-stalked, apically rounded with inamyloid rings. Ascospores 8.5–13 × 1.5–2.5 μm (av. = 10.5 × 2 μm, n = 30), irregularly arranged, allantoid, slightly or moderately curved, smooth, subhyaline, aseptate, usually with two oil droplets. Asexual morph: undetermined.

Culture characteristics. Ascospores germinating on PDA within 24 hours. Colonies on PDA, white when young, became pale brown, dense, but thinning towards edge, fluffy to slightly fluffy, white from above, pale brown from below, no pigmentation produced on PDA medium, no conidia observed on PDAor on OA media.

Specimens examined. China, Hainan Province, Wuzhishan City, Wuzhishan Nature Reserve (18°54’21.81″N, 109°40’54.12″E) on branches of unidentified plant, 14 November 2020. Altitude: 775 m. Y.H. Pi & Q.R. Li, WZS59 (GMB0054, holotype, KUN-HKAS 112700, isotype, ex-type living culture GMBC0054).

Additional specimen examined. China, Hainan Province, Wuzhishan City, Wuzhishan Nature Reserve (18°54’21.81″N, 109°40’54.12″E) on branches of an uni-dentified plant, 14 November 2020. Altitude: 775 m, Y.H. Pi & Q.R. Li, WZS66 (GMB0055, living culture GMBC0055)

Additional sequences. GMB0054 (LSU: MW797055, RPB2: MW814900); GMB0055 (LSU: MW797056, RPB2 MW814901).

Note. A peculiar feature of Pseudodiatrype hainanensis is the composition of endos- troma. There are black outer layer cells, white inner layer cells and powdery, yellowish cells that are smaller than the white cells at the edge of the endostroma near the black cells in endostroma.

Figure 3. Pseudodiatrype hainanensis (GMB0054, holotype) A stromata on host substrate B, C stromata on host D transverse section through ascostroma E vertical section through ascostroma F culture on PDA G section through the ascostroma H ostiolar canal I peridium J–M ascospores N–P asci. Scale bars: 40 μm (G); 10 μm (H–P).