Pleosporales » Morosphaeriaceae » Helicascus

Helicascus elaterascus

Helicascus elaterascus (Shearer) H. Zhang & K.D. Hyde, Cryptog. Mycol. 33: 158 (2012)

Facesoffungi number: FoF02018


Saprobic on decaying, submerged wood in freshwater. Sexual morph: Ascomata 200–300 µm high × 165–180 µm diameter, immersed, solitary, aggregated, subglobose to ellipsoidal, black, periphysate ostiolar neck, papillate. Peridium 26–55 µm, composed of several layers of brown to dark brown cells of textura angularis, outer layer dark brown, inner layer of hyaline, flattened cells of textura angularis, 2–3 µm wide. Asci 88–130 × 18–23 µm (x̄ = 101 × 20, n = 15), 8-spored, bitunicate, cylindric-clavate, long pedicellate, form a long tail-like extension, apically rounded. Ascospores 20–27 × 8–12 µm (x̄ = 25 × 10, n = 20), 2-seriate partially overlapping, hyaline when young and brown when mature, ellipsoid-fusiform, upper cell wider, tapering towards the narrow end, 1-septate, constricted at the septum, refractively guttulate, smooth-walled, with or without mucilaginous sheath. Asexual morph: Undetermined.


Culture characteristics: Ascospores germinated on WA within 24 hours. Colonies on MEA, circular, flat surface, wavy margin, reaching 0.2–0.5 cm diameter in 5 days at 25 °C, at first white to pale yellow, later becoming brown, white and brown at the edge and dark brown at reverse side.


Known distribution: Hong Kong (Kodsueb et al. 2004), Japan (Tanaka et al. 2015), Thailand (this study).


Known substrates: On dead wood and submerged twigs of woody plant of unidentified hosts (Tanaka et al. 2015), on submerged wood (Kodsueb et al. 2004, this study).


Material examined: Thailand, Phayao, on submerged wood in a freshwater stream, 11 September 2017, S. Boonmee, PK98 (MFLU 18–1089, new geographical record); living culture (MFLUCC 17–2573).


GenBank numbers: ITS: MN608548, LSU: MN577417, tef1: MN612111.


Notes: Helicascus elaterascus (MFLUCC 17–2573) was collected from decaying submerged wood in freshwater stream in Phayao Province, Thailand. Our strain shares similarities in ascomata, asci and ascospores with Helicascus elaterascus strains KT 2673, KT 2682 and HKUCC 7769. Multi-gene phylogenetic analysis placed our strain among H. elaterascus strains with 67% ML support.