Stagonospora (Sacc.) Sacc., Syll. fung. (Abellini) 3: 445 (1884)
Facesoffungi number: FoF 07599
Dothideomycetes, Pleosporomycetidae, Pleosporales, Massarinaceae
Saprobic on dead stem of host plant. Sexual morph: see Quaedvlieg et al. (2013). Asexual morph: Conidiomata black, pycnidial, solitary to gregarious, immersed to semi-immersed, globose to subglobose or depressed globose, unilocular, glabrous or setose, ostiolate. Ostiole single, circular, centrally located. Conidiomatal wall composed of thick-walled, dark brown cells of textura angularis in the outer layers, becoming hyaline, small cells towards conidial hymenium. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, holoblastic, occasionally annellidic, doliiform or ampulliform to broadly conical, indeterminate, discrete, smooth-walled, and formed from the inner wall layer of conidiomata. Conidia hyaline, cylindrical to fusiform, with an obtuse apex and a subtruncate base, straight or slightly curved, with several transverse eusepta, smooth-walled, guttulate, with or without mucoid, apical appendage (adapted from Sutton 1980, Hyde et al. 2016).
Type species: Stagonospora paludosa (Sacc. & Speg.) Sacc., Syll. fung. (Abellini) 3: 453 (1884)
Notes: Stagonospora can be confused with Septoria, as both genera have similar forms of conidiomata and conidia. Septoria was separated from Stagonospora on the basis that Stagonospora has percurrently proliferating conidiogenous cells, whereas in Septoria they proliferate sympodially (Quaedvlieg et al. 2013). However, some Septoria species also have percurrently proliferating conidiogenous cells (Quaedvlieg et al. 2013). Thus conidiogenesis alone is not a sufficient character to define genera. Quaedvlieg et al. (2013) epitypified S. paludosa and revealed that Stagonospora sensu stricto belongs to Massarinaceae, while Septoria sensu stricto was placed in Mycosphaerellaceae. Tanaka et al. (2015) and Hyde et al. (2016) included two species (S. paspali, S. forlicesenensis), which enlarged the generic concepts of Stagonospora to include neottiosporina-like asexual morphs. Furthermore, the sequences of Neottiosporina cylindrica (LSU: MH423484, MH423486, ITS: MH423484, MH423483, MH423482) are closely related to some Stagonospora species (e.g., S. trichophoricola, S. forlicesenensis, S. victoriana, S. pseudoperfecta), therefore it was transferred to Stagonospora. Neottiosporina has been separated from Stagonospora by its conidia bearing mucoid, apical appendages. However, Crous et al. (2012b) showed that conidia appendages morphology alone is not informative at the generic level. Therefore, Neottiosporina might be congeneric with Stagonospora. To clarify the taxonomy of Neottiosporina and Stagonospora, the type species of Neottiosporina (N. apoda (Speg.) Subram.) will have to be recollected, and epitypified, so that authentic cultures and DNA sequence can confirm this hypothesis.
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.