Fissuroma thailandicum Phookamsak & K.D. Hyde, sp. nov.
Index Fungorum number: IF551631

Etymology: The epithet Bthailandicum^ refers to the country,
from which the fungus was collected.
Holotype: MFLU 11-0156

Saprobic on bamboo. Sexual morph: Ascostromata 210–390μm high, 650–1050μm diam., dark brown, scattered, gregarious, immersed beneath host epidermis, visible as numerous, raised, dome-shaped areas on the host surface, hemisphaerical, with flattened base and wedge-shaped at the sides, uni-loculate, glabrous, coriaceous, ostiolate. Ostioles central, apapillate, waxy, with slit-like opening, carbonaceous at the rim. Peridium 15–70μm wide, of unequal thickness, poorly developed at the apex, thick at sides towards the apex, composed of several layers, of dark brown to black, pseudoparenchymatous cells, with host cells plus fungal tissue, arranged in a textura angularis to textura epidermoidea, with palisade-like cells at the rim. Hamathecium composed of dense, 0.9–1.8μm wide, filamentous, trabeculate pseudoparaphyses, anastomosing at the apex, embedded in a hyaline gelatinousmatrix. Asci (150–)170–190(– 204)×15–18(–19.5) μm (x =176.9×17μm, n=30), 8-spored, bitunicate, cylindrical to cylindric-clavate, with short furcate to truncate pedicel, apically rounded, with an obtuse ocular chamber. Ascospores (40–)43–46(–52)×6–7(–9) μm (x =45.4×7.1μm, n=30), overlapping bi- to tri-seriate at the base, uniseriate at the apex, hyaline, fusiform with acute ends, 1-septate, slightly constricted at the septum, upper cell wider and shorter than lower cell, smooth-walled, surrounded by a thick, distinct, mucilaginous sheath. Asexual morph: Undetermined.

Culture characteristics: Colonies on MEA reaching 14–17 mm diam. after 2 weeks at 25–30 °C, colonies circular, medium dense, flattened, slightly raised to umbonate, dull, smooth with edge entire, woolly, slightly radiating; from above, white to yellowish-grey at the margin, yellowish-grey to dark grey at the centre; from below: pale yellowish to yellowish-brown at the margin, yellowish-grey at the center, forming reddish-brown, concentric rings, seperating the centre from the margin; not producing pigmentation in agar.

Material examined: THAILAND, Chiang Rai Province, Mae Jun District, Huai Kang Pla Waterfall, on dead branch of bamboo, 25 October 2010, R. Phookamsak, RP0035 (MFLU 11-0156, holotype), living culture, MFLUCC 11-0206, BCC; ibid., Muang District, Khun Korn Waterfall, on dead stem of bamboo, 17 December 2010, R. Phookamsak, RP0105 (MFLU 11-0225), living culture, MFLUCC 11-0189, BCC.

Notes: Fissuroma thailandicum is most similar to F. bambusae and the differences are discussed under that species.

 

 

Fig. 1 Fissuroma thailandicum (MFLU 11-0156, holotype). a Appearance of ascostromata on host surface. b Section through ascostroma. c, d Section through peridium. e Pseudoparaphyses. f, g Asci. h–j Ascospores. k Ascospore stained in Indian ink. l Germination of ascospore. Scale bars: b=200μm, e–h=50μm, c=20μm, d, i–l=10μm