Psiloglonium macrosporum Thambugala, Senan. & K.D. Hyde, sp. nov.
Index Fungorum number: IF 551806, Facesoffungi number: FoF 01774, Fig. 2
Etymology: Referring to its relatively large ascospores
Holotype: MFLU 14–0610

Saprobic on decaying wood. Sexual morph Ascomata 600 – 1400 μm long × 275 – 475 μm wide × 270 – 415 μm high (x̄ = 921 × 348 × 327 μm, n = 6), hysterothecial, scattered, superficial, base immersed in the substrate, elongate and depressed conchate, globose, surface black, shiny, longitudinally striate, apex compressed, opening by a longitudinal slit. Peridium 30 – 60 μm (x̄ = 42, n = 15) wide, carbonaceous, brittle, comprising heavily pigmented, small, prosenchymatous cells. Hamathecium comprising 0.5 – 1 μm wide, hyaline, aseptate, branched, trabeculate pseudoparaphyses, in a gelatinous matrix. Asci 168 – 215 × 50 – 60 μm (x̄ = 187 × 55 μm, n = 15), bitunicate, 8 – spored, oblong to clavate, with a very short pedicel or pedicellate, apically thickened, with a distinct ocular chamber. Ascospores 80 – 115 × 25 – 31 μm (x̄ = 98 × 28.4 μm, n = 25), crowded to biseriate, fusiform when young, oblong at maturity 80 – 113 × 25 – 31 μm (x̄ = 98 × 28.35 μm, n = 20), hyaline when young and becoming brown at maturity, smooth-walled, ornamented, surrounded by a mucilaginous sheath. Asexual morph Undetermined.

Material examined: THAILAND, Chiang Mai Province, Chom Thong District, Doi Inthanon National Park, on dead twig, 2 November 2012, I.C. Senanayake TL026 (MFLU 14–0610, holotype); ibid (PDD, isotype), ex-type living culture (MFLUCC 13–0448, ICMP 20755).

Culture characteristics: Ascospores germinating on PDA within 24 h. Colonies growing on PDA 2 cm diam. after 21 days at 25 °C, slow growing, circular, effuse, dense, gray, smooth surface with entire to slightly undulate edge.

Notes: Psiloglonium macrosporum is introduced here as a new species based on morphological traits and phylogeny. In the present phylogenetic analysis P. macrosporum grouped with other Psiloglonium species (Fig. 1) and is closely related to P. sasicola (N. Amano) E. Boehm & C. L. Schoch. Psiloglonium macrosporum differs from other Psiloglonium species in having 4 – spored asci and relatively large, brown ascospores with ornamentation.

Fig. 1 Phylogram generated from Maximum Likelihood (RAxML) analysis based on LSU sequence data of Hysteriaceae. Maximum likelihood bootstrap support values equal or greater than 50 % are indicated above and below the nodes. New taxa are in blue and sequences based on type material have names in bold. The tree is rooted with Delitschia winteri.

Fig. 2 Psiloglonium macrosporum (holotype) a, b Hysterothecia on host c Vertical section of hysterothecium d Apex of the hysterothecia e Peridium f Pseudoparaphyses g – i Asci j – m Ascospores. Scale bars: c = 150 μm, d, e, g – i = 50 μm, f = 10 μm, j – m = 40 μm.