Tubeufia longiseta D.Q. Dai & K.D. Hyde, sp. nov. Index Fungorum numbers: IF552029

Etymology: In reference to its ascomata with long setae.

Holotype: MFLU 15–1215

Saprobic on bamboo culm. Sexual morph: Ascomata 250–370 μm high, 180–250 μm diam., superficial, solitary, gregarious or in loosegroups, subglobose, oboviod, black, with a central ostiole. Setae 100–350 × 3.5–5.5 μm, dense, covering the whole ascoma, black, unbranched, septate, dark brown, thick-walled. Peridium 25–40 μm wide, composed of 7–11 layers of cells of textura angularis; outer stratum composed of large, dark brown, thick-walled, 11–21 × 6.5– 14.5 μm cells; inner stratum composed of small, hyaline, thin-walled cells. Hamathecium comprising 2–2.5 μm wide, septate, branched, hyaline, cellular pseudoparaphyses embedded in a gelatinous matrix. Asci 90–140 × 14.5–18 μm (x = 118.1 × 16.8 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical, short pedicellate, apically rounded, with an ocular chamber. Ascospores 38.5–55.5 × 4.5–6 μm (x = 47.3 × 5.6 μm, n = 20), long subfusiform, elongate, pointed at the ends, slightly curved, 10–13-septate, not constricted at the septa, hyaline, smooth-walled. Asexual morph: Undetermined.

Cultural characters: Ascospores germinating on PDA within 24 h. Colonies growing slowly on PDA, reaching 2 mm in 30 d at 28 °C, under 12 h light/12 h dark, effuse, velvety to hairy, edge fimbriate, olive to olive brown, darkbrown on PDA media. Mycelium superficial and partially immersed, branched, septate, pale brown to olivaceous brown,smooth, sterile at 60 days.

Material examined: THAILAND, Phang-Nga, Doi Nang Hong, Tham Thong Lang, Thap Put District, 8°32′11″N 98°33′35″E, on dead culms of bamboo, 6 October 2014, Kevin D. Hyde DDQ00287 (MFLU 15–1215, holotype); Ibid. (KUN HKAS88722, isotype), ex-type living cultures, MFLUCC 15–0188, KUMCC.

Notes: Tubeufia longiseta is similar to T. acacia in having superficial, subglobose, black ascomata, covered with black setae, cylindrical asci and long subfusiform, elongate ascospores. However, T. longiseta has smaller ascomata (250– 370 μm high, 180–250 μm diam. vs. 300–375 μm high, 225–255 μm diam.), ascospores with more transverse septa (10–13 vs. 5–7 septa), and is found on different substrates (bamboo vs. acacia). Black ascomata with long, black setae can be observed in several genera of Tubeufiaceae, such as Acanthohelicospora, Acanthostigma, Chlamydotubeufia, Helicangiospora, Neocanthostigma and Thaxteriellopsis (Boonmee et al. 2014). However, phylogenetic analyses confirm that this new taxon belongs to Tubeufia sensu stricto and is closely related to T. javanica (Fig. 26). The latter species differs in having white to yellowish, oblong to clavate ascomata and broad, filiform ascospores (Boonmee et al. 2014).

FIG Tubeufia longiseta (MFLU 15–1215, holotype). a Herbarium specimen. b–d Black ascomata with setae on host surface. e, f Vertical sections of ascomata. g Peridium. h Dark brown setae. i–k Asci. l, m Sterile cells from PDA. n, o Cultures on PDA. p–t Ascospores. u Germinating ascospore. Scale bars: a = 5 mm, b–d = 1 mm, e–g = 50 μm, h–u = 10 μm.