Fissuroma fissuristoma (J. Fröhl et al.) Phookamsak & K.D. Hyde, comb. nov.
Astrosphaeriella fissuristoma J. Fröhl., K.D. Hyde & Aptroot, in Hyde, Aptroot, Fröhlich&Taylor, Nova Hedwigia 70(1–2): 147 (2000)
Index Fungorum number: IF551636

Saprobic on Calamus conirostris Becc. Sexual morph: Ascostromata 300–390μm high, 750–1030μm diam., black, scattered, gregarious, immersed beneath host epidermis, visible as raised, glistening, dome-shaped, dark regions on the host surface, hemisphaerical, with flattened base, uni-loculate, glabrous, walls smooth, coriaceous, ostiolate. Ostioles central, apapillate, with long carbonaceous, and thick, slit-like opening, comprising several layers of small, black cells, of textura globulosa. Peridium 20–70(–90) μm wide, of unequal thickness, poorly developed at the base, composed of dark brown to black, pseudoparenchymatous
cells, with host cells plus fungal tissue, arranged in textura angularis to textura prismatica, with palisade-like cells at the rim, carbonaceous at the apex. Hamathecium composed of dense, 0.8–1.8μm wide, filiform, trabeculate pseudoparaphyses, anastomosing among the asci, embedded in a hyaline gelatinous matrix. Asci (124–)130–150(–166)×(16–)18–19(–26) μm (x =144.1× 19.3μm, n=30), 8-spored, bitunicate, obclavate, with subsessile to short, knob-like pedicel, apically rounded, with an ocular chamber. Ascospores (43–)45–50(–55)×7–9μm (x =48.2×8.4μm, n=30), overlapping bi- to triseriate at the base, uni-seriate at the apex, hyaline, fusiform
with acute ends, 1-septate, becoming brown with 3 septa at maturity, slightly constricted at the central septum, smoothwalled, surrounded by a thin, distinct sheath, with appendages at both ends. Asexual morph: Undetermined.

Material examined: BRUNEI DARUSSALAM, Temburong, Batu Apoi Forest Reserve, Sungai Belalong, Kuala Belalong Field Studies Centre (KBFSC), Ashton’s Trail, on dead rattan and petiole base of Calamus conirostris Becc., January 1994, J. Fröhlich, IFRD 294-002 (HKU(M) JF 238, holotype).

Notes: Hyde et al. (2000) introduced Astrosphaeriella fissuristoma to accommodate a lophiostoma-like species with trabeculate pseudoparaphyses and long slit-like ostioles. The species is most similar to Astrosphaeriella mangrovei, but differs in habitat and ascospore size (Hyde et al. 2000). Suetrong et al. (2009) found that A. mangrovis was not congeneric with Astrosphaeriella. Therefore, the genus Rimora was introduced to accommodate Rimora mangrovei in Aigialaceae which was previously identified as Astrosphaeriella mangrovis (Suetrong et al. 2009). Additionally, Liu et al. (2011) introduced a new genus Fissuroma to accommodate lophiostoma-like species with trabeculate pseudoparaphyses and slit-like ostioles which were described as Astrosphaeriella species
in Hyde et al. (2000) and Tanaka and Harada (2005). Two Fissuroma species were phylogenetically confirmed in the family Aigialaceae. In this study, we examined the type of Astrosphaeriella fissuristoma and found that the species is morphologically similar to the species in Fissuroma. Therefore, we transfer Astrosphaeriella fissuristoma to Fissuroma.

Fig. 1 Fissuroma fissuristoma (IFRD 294-002, holotype of Astrosphaeriella fissuristoma). a Appearance of ascostromata on host surface. b Section through ascostroma. c–e Section through peridium. f Asci embedded in trabeculate pseudoparaphyses. g, h Asci. i, j
Ascospores. k Ascospores at maturity. l Ascospore stained in Indian ink. Scale bars: b=200μm, c=50μm, d–h=20μm, i–l=10μm