Ascomycota, genera incertae sedis
Saprobic on the host plant in terrestrial habitat, such as Salix alba, Salix sp. (Salicaceae). Sexual morph: undetermined. Asexual morph: Conidiomata brown, stromatic, pycnidial, solitary, semi-immersed, elongate globose, unilocular, glabrous, ostiolate. Ostiole subcylindrical, centrally located, with a rostrate apex extending above the substrate. Conidiomatal wall composed of thick-walled, dark brown to pale brown cells of elongated textura intricate to textura angularis. Conidiophores arising from the inner layer of the conidiomata, hyaline, branched, septate, smooth-walled. Conidiogenous cells hyaline, enteroblastic, phialidic, cylindrical to lageniform, integrated or discrete, determinate, smooth-walled, formed as short or long lateral branches from the conidiophores immediately below septa, with a minute apical channel and collarette. Conidia hyaline, cylindrical to allantoid, straight or slightly curved, unicellular, smooth-walled, eguttulate (Sutton 1980).
Type species: Cytonaema spinella (Kalchbr.) Höhn., Sber. Akad. Wiss. Wien, Math.-naturw. Kl., Abt. 1 123: 84 (1914)
Notes: Cytonaema shares a similar form of conidia with Cytospora, but differs in unilocular conidiomata with rostrate ostiole. Three taxa are placed in the genus, C. proteae Marinc., M.J. Wingf. & Crous, C. quercinum Potl. and C. spinella (Potlaichuk 1964, Sutton 1980, Marincowitz et al. 2008). No sexual morph has been linked to this genus and no molecular data is available. Cytonaema species have been reported as a producer of human cytomegalovirus protease inhibitors (Guo et al. 2000). Future study with a lager number of collections are needed to study the chemistry of Cytonaema.
Distribution: Argentina, Austria, Germany, Italy, New Zealand, Poland, Slovakia, UAS (Sutton 1980, https://www.gbif.org/).
Cytonaema spinella (redrawn from Sutton 1980) a Condia. b Vertical section of conidioma. c Conidiophores, conidiogenous cells and developing 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.