The genusAstrosphaeriellaSydow has been regarded as a synonym ofMicrotheliaKörber in recent surveys of bitunicate pyrenomycetes. The structure of the ascomata and the presence of trabeculate pseudoparaphyses show that it belongs to the series of melanommataceous pyrenomycetes and is unrelated to the pleosporaceous taxa commonly referred toMicrothelia.All taxa which have been referred toAstrosphaeriella, Astrotheca, orAsterothecaare revised and four species accepted:A. aosimensisHino&Katumoto,A. stellata(Pat.) Sacc.,A. trochus(Penzig&Sacc.) D. Hawksw. andA. venezuelensisBarr&D. Hawksw. As circumscribed here, the genus is exclusively tropical, comprising species characteristically occurring on petioles of palms and bamboo culms. Notes on excluded taxa are provided and the new combinationMycomicrothelia inaequalis(Fabre) D. Hawksw. is made