Oncosporella P. Karst., Meddn Soc. Fauna Flora fenn. 14: 105 (1887)
Faceoffungi number: FoF 07479
Ascomycota, genera incertae sedis
Saprobic on dead wood of Populus sp. (Salicaceae). Sexual morph: undetermined. Asexual morph: Conidiomata dark brown to black, stromatic, solitary, superficial, cupulate. Ostiole absent. Conidiomatal wall composed of thick-walled, pale brown to hyaline cells of textura angularis in the basal region, becoming thick-walled, dark brown cells of textura porrecta in the lateral region. Conidiophores arising from the inner wall layer of basal stroma, pale brown to hyaline, cylindrical, branched and septate at the base, smooth-walled. Conidiogenous cells hyaline, holoblastic, sympodial, cylindrical to irregular, integrated, indeterminate, smooth-walled, with 1–3 flat, unthickened, slightly protuberant scars towards the apices. Conidia hyaline, cylindrical to subcylindrical or lunate, rounded at the apex, truncate at the base, straight or slightly curved, up to 7-septate, smooth-walled, guttulate (Sutton 1980).
Type species: Oncosporella punctiformis P. Karst., Meddn Soc. Fauna Flora fenn. 14: 105 (1887)
Notes: Oncosporella is a monotypic genus. This genus has hyaline, cylindrical to subcylindrical, multi-septate conidia, which is similar to Parastagonospora (e.g., P. caricis) and asexual morph of Ascocalyx (= Bothrodiscus). However, Parastagonospora has enteroblastic, phialidic, determinate conidiogenous cells distinguished from the holoblastic, sympodial, integrated, indeterminate conidiogenous cells in asexual morph of Ascocalyx and Oncosporella. The asexual morph of Ascocalyx can be distinguished from Oncosporella by its stromatic, pycnidial conidiomata with broadly stipitate and numerous locules at one level concealed by incurved margin. Oncosporella has not been linked to its sexual morph, or studied by molecular methods. Fresh collections are needed to place it in a natural group.
Distribution: Finland (Sutton 1980)
Oncosporella punctiformis (redrawn from Sutton 1980) a Vertical section of conidioma. b Conidiophores, conidiogenous cells and developing conidia. c Conidia.
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.