Palmiascoma gregariascomum Phookamsak & K.D. Hyde, Fungal Divers 72: 65 (2015) Fig. 55

MycoBank number: MB 550927; Index Fungorum number: IF 550927; Facesoffungi number: FoF 00429.

Saprobic on dead branches of Eucalyptus. Sexual morph: (see Liu et al. 2015). Asexual morph: Conidiomata 85–205 μm high × 90–250 μm diam., (x̅ = 123 × 200 μm, n = 15), pycnidial, solitary, black, solitary to gregarious, aggregated, immersed to semi-immersed, when cut through horizontally locules visible as the black contents and black ascospore dots, globose to subglobose, glabrous, ostiole central, with minute papilla. Ostiole 30–40 μm high, 25–45 μm wide, central, short, slightly sunken, inconspicuous at the surface, periphyses. Conidiomata walls 40–90 μm wide, two layers, composed of cells of textura angularis, outer layer black to reddish brown, thick- walled, inner layer comprising 5–7 cell layers, light brown to hyaline, thin-walled. Conidiophores arising from basal cavity of conidiomata mostly reduced to conidiogenous cells, macronematous. Conidiogenous cells discrete, monoblastic, integrated, terminal, ampulliform to cylindrical, hyaline to subhyaline, simple, smooth-walled. Conidia 3–4.5 × 1.7–3 μm (x̅ = 3.8 × 2.3 μm, n = 30), solitary, oblong to ellipsoidal, initially hyaline, becoming pale brown to brown at maturity, aseptate, with rounded or obtuse ends, smooth-walled.

Material examined – Thailand, Chiang Rai, Muang District, Thasud Sub district, on dead branches of Eucalyptus sp. (Myrtaceae), 5 October 2011, M. Doilom, (MFLU 12-0752), living culture MFLUCC 11-0424.

Notes – Palmiascoma is a monotypic genus with P. gregariascomum as the type and was assigned in Bambusicolaceae (Liu et al. 2015). The species was introduced with both asexual and sexual morphs. The sexual morph occurred on dead frond of palm and asexual morph found on bamboo pieces (Liu et al. 2015). Our new collection of P. gregariascomum differs from the type specimen in having shorter and narrower conidia. This may be because of different substrates. Phylogenetic analyses (Fig. 42) indicate that our collection clusters with P. gregariascomum (MFLUCC 11-0175) as the same species with high support (100 % MLBS, 1.0 PP). We hereby illustrate this taxon as a new record on Eucalyptus sp.

Figure 55 – Palmiascoma gregariascomum (MFLU 12-0752, new host record). a Conidiomata on dead branch of Eucalyptus. b Close up conidiomata on host substrate. c Conidiomata cut through horizontally showing black and hyaline contents, (conidiomata of Palmiascoma gregariascomum showing in black contents (arrow). d Section through conidioma. e Close up conidia in conidioma. f Peridium. g, h Conidia attached to conidiophores. i Conidia. Scale bars: d = 100 µm, e = 50 µm, f, h = 20 µm, g, i = 5 µm.