Multiseptospora thysanolaenae Phookamsak, Ariyawansa & K.D. Hyde, sp. nov.
Index Fungorum number: IF 551948, Facesoffungi number: FoF 01660, Fig. 2
Etymology: The specific epithet “thysanolaenae” refers to the host.
Holotypus: MFLU 11–0238

Saprobic on Thysanolaena maxima Kuntze. Sexual morph Ascostromata 190 – 270 μm high, 300 – 350 μm diam., gregarious, scaterred, immersed, visible as raised, black dots on host surface, uni-loculate, globose to subglobose, glabrous, ostiole central, with minute papilla. Peridium 12 – 40μm wide, thin – to thick – walled, slightly thick at the sides towards apex, composed of several layers of flattened, pseudoparenchymatous cells, inner layers comprising flattened, hyaline cells, arranged in a textura prismatica, outer layers comprising brown to dark brown cells, arranged in a textura angularis. Hamathecium composed of dense, 1.8 – 4 μm wide, cellular pseudoparaphyses, slightly constricted at the septum, anastomosing among the asci, embedded in a hyaline gelatinous matrix. Asci (93–) 100 – 120 (–143) × (26–) 28 – 32 (–35) μm (x̄ = 114.3 × 30.4 μm, n = 30), 8 – spored, bitunicate, fissitunicate, broadly cylindric-clavate to clavate, subsessile to short pedicellate, apically rounded, with an indistinct ocular chamber. Ascospores (55–) 60 – 65 (–73) × (8–) 9 – 11 (–13) μm (x̄ = 64.6 × 10.5 μm, n = 30), overlapping 3 – 4-seriate, initially hyaline, becoming brown to dark brown at maturity, fusiform, with slightly rounded ends, slighty curved, (6–) 7 – septate, not constricted at the septa, smooth-walled, surrounded by thin, mucilaginous sheath, with small appendages at both ends. Asexual morph Undetermined.

Culture characteristics: Colonies on PDA fast growing, reaching 70 – 80 mm diam. after 4 weeks at 25 – 30 °C, colony from above, light brown to dark brown; from below: black; dense, circular, slightly raised to umbonate, surface smooth, dull with entire edge, concave at the centre, fluffy to floccose, producing brown pigmentation in agar.

Material examined: THAILAND, Chiang Mai, Doi Suthep-Pui, on dead leaf sheath of Thysanolaena maxima (Poaceae), 5 June 2011, R. Phookamsak, RP0118 (MFLU 11–0238, holotype), ex-type living culture, MFLUCC 11– 0202, BCC.

Notes: Multiseptospora thysanolaenae is similar to the type species, M. thalandica in having multi-septate ascospores and is associated with Thysanolaena maxima Kuntze. However, M. thysanolaenae differs from M. thailandica due to its glabrous ascostromata, with brown ascospores. Multiseptospora thysanolaenae has larger ascomata, asci and ascospores than M. thailandica, but has less ascospore septation (ascospores septation: 10 – 11 – septate in M. thailandica versus 6 – 7 – septate in M. thysanolaenae. Based on phylogenetic analysis, M. thysanolaenae clusters with M. thailandica (Fig. 1).

Fig. 1 Phylogram generated from maximum likelihood analysis based on combined LSU, SSU, RPB2 and TEF sequence data of Pleosporineae and Massarineae, Pleosporales, Dothideomycetes. Maximum likelihood bootstrap support values greater than 50 % are near the nodes. The extype strains are in bold and the new isolates are in blue. The tree is rooted with Halotthia posidoniae BBH 22481

Fig. 2 Multiseptospora thysanolaenae (holotype) a Appearance of ascostromata on host surface b Section through an ascostroma c Section through peridium d Pseudoparaphyses stained in Indian ink e Asci with pseudoparaphyses f – h Asci I – l Ascospores m Ascospore stained in Indian ink n Spore germination on WA after 8 h. Scale bars: b = 100 μm, c, e = 50 μm, d, f – n = 20μm.