Fungalpedia – Note 2051, Mytilinidiaceae
Mytilinidiaceae. Kirschst.
Citation when using this data: Hongsanan S et al. 2020 – Fungalpedia, Ascomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank
Classification: Mytilinidiales, Pleosporomycetidae, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi
Saprobic on wood, bark, resin, cones, scales, needles, seeds, and roots of gymnosperms, much less frequently on angiosperms. Predominantly temperate in distribution. Sexual morph: Ascomata superficial, scattered to gregarious, black, sometimes less connivent, more appressed, hysterioid, grouped in triangular or radiating star-shaped or astral arrangement, fragile, yet persistent, carbonaceous, globoid to obovoid, to strongly laterally compressed erect, bivalve shell-shaped structures, standing on edge, with lateral walls more or less connivent, and extended vertically to a prominent longitudinal keel or cristate apex; distinctly clam- or musselshaped. Peridium fragile, thin-walled, scleroparenchymatous, rarely of multiple layers. Hamathecium comprising narrow trabeculate pseudoparaphyses, borne gelatinous matrix, often sparse to lacking at maturity. Asci 8-spored, rarely 4-spored, bitunicate, fissitunicate, cylindrical, with a broad, short pedicel, ocular chamber not well developed, borne on a basal cushion, centrally orientated within the centrum, rarely borne laterally. Ascospores overlapping 1–2-seriate or in one or two fascicles within the ascus, hyaline to pigmented yellow to dark brown, highly variable in septation, showing bipolar symmetry. Asexual morph: Primarily coelomycetous or less frequently hyphomycetous (Lohman 1932, 1933a, b, Blackwell & Gilbertson 1985, Speer 1986).
Notes – The genera Mytilinidion, Lophium and Quasiconcha formed a monophyletic clade, representing Mytilinidiales (Boehm et al. 2009b). The conchate nature of the hysterothecia and the thin-walled peridium are characteristic features of this group (Boehm et al. 2009a, b, Hyde et al. 2013). Although, Boehm et al. (2009a) and Hyde et al. (2013) mentioned that Mytilinidiaceae have trabeculate pseudoparaphyses, Mytilinidion didymospora introduced by Jayasiri et al. (2018) has cellular-like pseudoparaphyses (see Jayasiri 2018). Several species of Mytilinidiaceae were shown without clear pictures of hamathecium, thus we suggest that morphological study of hamathecium is needed for future works.
Our multi-gene phylogenetic analysis confirms the placement of Mytilinidiales within the class Dothideomycetes. Gloniales is introduced in this study based on their diverse morphology. Therefore, the Mytilinidiales is a monotypic order with Mytilinidiaceae.
Type genus: Mytilinidion Duby,
Other accepted species: Species Fungorum – search Mytilinidiaceae.
References
Lohman ML. 1933a – Hysteriaceae: Life histories of certain species. Annual report of the Michigan Academy of Science 17, 229–288.
Lohman ML. 1933b – Septonema toruloideum: A stage of Mytilidion scolecosporum. Mycologia 25, 34–43.
Entry by
Sinang Hongsanan, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, People’s Republic of China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50002, Thailand
Published online 23 March 2026