Neodidymella thailandicum Phookamsak, R.H. Perera & K.D. Hyde.
Index Fungorum number: IF551390; Facesoffungi number: FoF00905; Fig. 1
Etymology – The generic epithet “thailandicum” refers to the country where the species was collected.
Holotype – MFLU 11-0176

Biotrophic or hemibiotrophic on living leaves of Calathea. Sexual morph: Ascomata 65 – 110 μm high, 80 – 130 μm diam., scattered, solitary to gregarious, visible as black dots on the lower epidermis, globose to subglobose, uni-loculate, glabrous, ostiole central, with pore – like opening. Peridium 8 – 20 μm wide, of equal thickness, composed of 2 – 3 layers of large, brown to dark brown, pseudoparenchymatous cells, arranged in a textura angularis. Hamathecium composed of dense, 2 – 5 μm wide, broad, cellular pseudoparaphyses, distinctly septate, constricted at the septum, branched, anastomosing at the apex, embedded in a gelatinous matrix. Asci (46–) 50 – 60 (−70) × (12–) 13 – 15 (−18) μm (x̄ = 54.8 × 13.8 μm, n = 25), initially 8 – spored, bitunicate, fissitunicate, broadly cylindrical to cylindric-clavate, sessile to subsessile, or short, bulbous pedicellate, with furcate pedicel, apically rounded, with indistinct ocular chamber. Ascospores (11) 12 – 13 (−14) × 4 – 5 (−6) μm (x̄ = 12.6 × 5.5 μm, n = 30), overlapping bi – seriate, hyaline, ellipsoidal to clavate, or fusiform with rounded ends, 1-septate, slightly constricted at the septum, wall echinulate. Asexual morph: Undetermined.

Culture characteristics – Colonies on MEA fast growing, 80 – 85 mm diam. after 2 weeks at 25 – 30 °C, colonies circular, medium dense, flat, smooth with entire edge, fairly fluffy to granular, slightly radiating; colonies in the upper part:white to cream at the margin, yellowish grey to pale yellowish at the middle and greyish yellow at the centre; reverse pale white to olive at the margin, yellowish greyish yellow at the centre; not producing pigmentation.

Material examined – THAILAND, Chiang Rai, Muang District, Pakha Village, on living leaves of Calathea sp. (Marantaceae), 4 August 2010, R. Phookamsak RP0056 (MFLU11-0176), living culture MFLUCC 11-0140,KUMCC.

Fig. 1 Neodidymella thailandicum (holotype). a Appearance of ascomata on lower epidermis b Section through ascoma c Section through peridium d Asci with pseudoparaphyses e – g Asci h – l Ascospores m, n Culture characteristics (m = from above, n = from below). Scale bars: b = 50 μm, c – g = 20 μm, h – l = 5 μm.