Astrosphaeriella Sydow, a misunderstood genus of melanommataceous pyrenomycetes

The genus Astrosphaeriella Sydow has been regarded as a synonym of Microthelia Körber 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 to Microthelia. All taxa which have been referred to Astrosphaeriella, Astrotheca , or Asterotheca are revised and four species accepted: A. aosimensis Hino & Katumoto, A. stellata (Pat.) Sacc., A. trochus (Penzig & Sacc.) D. Hawksw. and A. venezuelensis Barr & 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 combination Mycomicrothelia inaequalis (Fabre) D. Hawksw. is made.