Dothideomycetes »Dothideomycetes, genera incertae sedis

Asteromella

Citation: Pem D et al. (2019) Mycosphere Notes 275-324: A morphotaxonomic revision and typification of obscure Dothideomycetes genera (incertae sedis). Mycosphere 10(1), 1115–1246

Asteromella Pass. & Thüm., in Thümen, Mycoth. Univ., cent.17: no. 1689 (1880)

Epifoliaron the upper surface of living leaves.Colonies forming blackened 0.2–0.4 mm circular areas.Sexual morph: Undetermined. Asexual morph:Pycnidia hypophyllous, dark brown to black, globose to subglobose, superficial with irregular margins, sometimes sparsely scattered or not entirely distributed on surface of leaves.Peridiumthick walled comprised of cells oftextura globulosa.Conidiophores reduced to conidiogenous cells.Conidiogenous cells enteroblastic, phialidic, integrated or less often discrete, determinate, hyaline (Sutton 1980, van der Aa & Vanev 2002).Conidia simple, cylindrical to ovoid, hyaline, 1–septate, ellipsoidal to cylindrical, eguttulate.

Type species–Asteromella ovataThüm.

Notes –Asteromella,introduced byPasserini &Thümen (1880), is a large genus of plant-inhabiting coelomycetous fungi presently referred to Dothideomycetesincertae sedis (Hyde et al. 2011, Wijayawardene et al. 2018). The type species,Asteromella ovata,is a coelomycetous fungus producing minute, bacteria-like spores and was found onleaves ofMenispermum canadense in Italy. The characteristics of the type species provided by Thümen (1880) are conidiomata, conidia and dark lesions of host plant leaves caused by the fungus. The genusAsteromellahas been critically monographed by Ruszkiewicz-Michalska (2016). Currently, there are around265 species listed (Index Fungorum 2019). The sexual morph is unknown.We did microscopic observation of the holotype specimen ofAsteromella ovatafrom S herbarium and compared morphological characters with the original protologue. Due to its ‘Phoma’ like conidia and limited morphological characters, we retain the genus to Dothideomycetes generaincertae sedis.