Phaeoappendicospora thailandensis Senan., Q.R. Li & K.D. Hyde, sp. nov., MycoBank: MB821573

Etymology: The species epithet is based on the collection locality.

Saprobic on dead stems of Quercus. Sexual morph: Stromata 2–4 mm diam (x̅ = 3 mm, n = 15), forming thin weft of pale brown hyphae around upper part of perithecia. Ascomata 180–230 μm high, 170–220 μm diam (x̅ = 208 × 198 μm, n = 25), immersed, aggregated, subglobose to globose, coriaceous, black, ostiolate, papillate. Papilla black, cylindrical, lateral, periphysate. Periphyses hyaline, filamentous. Peridium 20–35 μm wide (x = 28 μm, n = 20), comprising few layers of black, thick-walled cells of textura angularis. Hamathecium comprising few, septate, hyaline paraphyses attached to the base, longer than asci. Asci 195–265 × 18.5–27 μm (x̅ = 223 × 22.5 μm, n = 30), 8-spored, unitunicate, ellipsoid, with a short pedicel, inconspicuous, flat, J- refractive ring at the lower end of the thickened apical wall, apex narrow and blunted. Ascospores 26–34.5 × 11–13 μm (x̅ = 30 × 12.5 μm, n = 30), ellipsoidal to ovoid, with broadly rounded ends, pale brown, 1-septate, not constricted at the septa, thick and smooth-walled, guttulate, with short, hyaline, rounded appendages at both ends. Asexual morph: Undetermined.

Culture characteristics: Colonies on PDA reaching 5 cm in 7 d at 25 °C, fast growing, circular, flat, smooth, whitish cream in upper, pale yellow in reverse.

Specimen examined: Thailand, Chiang Rai, near Khun korn water fall, on branch of Quercus sp. (Fagaceae), 25 Dec. 2012, Q.R. Li, TL19 (holotype MFLU 12–2131, culture ex-type MFLUCC 13–0161).

Notes: The newly introduced monotypic genus Phaeoappendicospora is typified by P. thailandensis and it comprises brown ascospores with guttules and appendages. Phaeoappendicospora thailandensis is associated with dead plant parts may be as saprobes. This fungus is morphologically similar to Hapalocystis berkeleyi in Sydowiellaceae. However, phylogenetically it does not show an affinity to any of the families in Diaporthales. Hence, we accommodate this species in Diaporthales genera incertae sedis.

Figure 191 Phaeoappendicospora thailandensis (Material examined – THAILAND, Chiang Rai, near Khun Korn water fall, on branch of Quercus sp. (Fagaceae), 25 December 2012, Q.R. Li, TL19, MFLU 12–2131, holotype). a Appearance of fungus on host substrate. b Horizontal cross section of stroma. c Vertical cross section of stroma. d, e Asci. f-i Ascospores. Scale bars: a = 1 mm, b = 500 μm, c = 100 μm, d-i = 10 μm.