Hidakaea I. Hino & Katum., Bull. Faculty of Agriculture, Yamaguchi University 6: 38 (1955).
Index Fungorum number: IF 2336; Facesoffungi number: FoF 12236, 1 morphological species (Species Fungorum 2022), no molecular data available.
Saprobic or parasitic on stems of bamboo, causing black to brown spots. Sexual morph: Ascomata solitary or gregarious, flattened against the host surface, subglobose, in section hemispherical, brown, subcoriaceous but membranous at the base, smooth from above, unilocular, with a central ostiole. Peridium brown-black at the sides, other parts light brown, in the sagittal section, comprising a few layers of cells, outer cells appear pseudoparenchymatous and cell wall very thin, on the base cells isodiametric, black-brown. Hamathecium comprising paraphyses, embedded in mucilage, and longer than asci. Asci 8-spored, unitunicate, cylindrical-clavate or oblong, with a short pedicel apically rounded with inconspicuous apical structure. Ascospores 2-seriate, fusiform, tapering gradually at one or both ends, or pointed, hyaline or pale, 3-septate, slightly constricted at septa, smooth walled, some with sheath. Asexual morph: Unknown (adapted from Wu et al. 2010).
Type species: Hidakaea tumidula I. Hino & Katum.
Notes: Hidakaea is characterised by solitary or gregarious ascomata, cylindrical-clavate or oblong asci and 2-seriate, fusiform ascospores. Hino and Katumoto (1955) suggested the placement of Hidakaea in Microthyriaceae based on ascomata with a scutate structure, superficial subglobose ostiolate ascomata, and bitunicate, clavate or cylindrical-clavate asci. Wu et al. (2010) re-examined the holotype of H. tumidula (YAM 20296) and did not find the scutate structure and bitunicate asci as described in the protologue. Wu et al. (2010) reported that Hidakaea does not belong in Dothideales and Microthyriaceae since it has unitunicate ascus. Wu et al. (2010) suggested the placement of Hidakaea in Sordariomycetes having affinities with the Chaetosphaeriales or Hypocreales. Hidakaea resembles members of Hypocreales in having brown ascomata and similar characters of asci and ascospores. Wu et al. (2010) referred Hidakaea to Hypocreales incertae sedis. Kirk et al. (2013), and Wijayawardene et al. (2017, 2020) placed Hidakaea in Dothideomycetes genera incertae sedis. Sequence data is lacking. Fresh specimen with DNA sequence data are needed to confirm the generic placement of Hidakaea.