Wettsteinina Höhn., Sber. Akad. Wiss. Wien, Math. -naturw. Kl., Abt. 1 116: 126 (1907).
Index Fungorum number: IF 5773; Facesoffungi number: FoF 12529, 46 morphological species (Species Fungorum 2022), molecular data available for 5 species and some unnamed species.
Hemibiotrophic or saprobic. Sexual morph: Ascomata generally small, scattered, immersed with a protruding broad papilla. Peridium very thin, composed of few layers of thin-walled large polygonal cells in surface view. Hamathecium deliquescing at maturity. Asci bitunicate, fissitunicate, sub globose to obpyriform, without a pedicel, with small truncate ocular chamber. Ascospores hyaline and turning pale brown when mature, septate, upper second cell enlarged, slightly constricted at the second septum, smooth, surrounded by a hyaline gelatinous sheath. Asexual morph: Stagonospora (Farr et al. 1989) (adapted from Zhang et al. 2012).
Type species: Wettsteinina gigantospora (Rehm) Höhn.
Notes: Wettsteinina is characterised by small, scattered ascomata, subglobose to obpyriform asci and hyaline ascospores turning pale brown surrounded by a hyaline gelatinous sheath. Confusion exists regarding the type species of Wettsteinina. Höhnel (1907) mentioned W. gigaspora as the first species when introducing Wettsteinina and introduced Pseudosphaeriaceae to accommodate Wettsteinina. However, Locquin (1972) erected Wettsteininaceae (as Wettsteiniaceae). Clements and Shear (1931) accepted W. gigaspora as the type species of Wettsteinina and this was followed by Shoemaker and Babcock (1987). Theissen and Sydow (1918), familiarized a new order, Pseudosphaeriales to accommodate Wettsteinina and its synonym Pseudosphaeria. Shoemaker and Babcock (1987) added Wettsteinina to Pleosporaceae based on its “Pleospora-type” centrum and treated Pseudosphaeriaceae and Wettsteininaceae as synonyms of Pleosporaceae. Based on Index Fungorum (http:// www.indexfungorum.org, January 2022), the type species of Wettsteinina is W. gigantospora. Both W. gigantospora and W. gigaspora are considered as synonyms of W. mirabilis (Zhang et al. 2012). Zhang et al. (2012) described the type species W. gigantospora representing the type of W. gigaspora. In the phylogenetic analysis of Kodsueb et al. (2006a) based on LSU sequence data, W. macrotheca, W. pachyasca and W. dryadis were reported to be closely related to Pleomassaria siparia (Melanommataceae) while in the analysis of Schoch et al. (2009) based on SSU, nucLSU rDNA, TEF1, RPB1 and RPB2, W. lacustris nested within Lentitheciaceae. Wettsteinina resembles members of Capnodiales and Venturiales in having asymmetrical ascospores, thick-walled obpyriform asci and absence of pseudoparaphyses (Zhang et al. 2012). The type species of Wettsteinina has not been sequenced. Lumbsch and Huhndorf (2010), Kirk et al. (2013) and Wijayawardene et al. (2017, 2020) listed Wettsteinina in Dothideomycetes genera incertae sedis. Fresh collections with DNA sequence data are needed to confirm the systematic position of Wettsteinina. The generic type must be sequenced to understand the taxonomy of Wettsteinina. Molecular markers are available for Wettsteinina dryadis (ITS and LSU), W. lacustris (SSU, RPB2, TEF-1 and mtSSU), W. macrotheca (LSU), W. pachyasca (LSU) and W. philadelphi (ITS, LSU and TEF-1).