The genus Podocrella and its nematode-killing anamorph Harposporium

Several genera are described in the literature as having morphology similar to the clavicipitaceous genus Podocrella, viz. Atricordyceps, Ophiocordyceps, Wakefieldiomyces and "Cordyceps" peltata. These genera have capitate-stipitate stromata that gradually expand into a horizontally flattened fertile head that is dark, has strongly protruding perithecia and asci containing eight multiseptate filiform ascospores. These ascospores disarticulate at the middle septum to form two lanceolate multiseptate part-as-cospores. In this study several specimens of the above-mentioned genera, including the types, were examined to determine whether they are congeneric with Podocrella. This study also reveals the connection of Podocrella to its anamorph genus, Harposporium, and its relationship to several other clavicipitaceous genera, based on cultural data and large subunit nuclear ribosomal DNA (LSU) sequences. Nematode predation of the Harposporium anamorph of P. peltata is demonstrated. The results show Podocrella and selected Harposporium LSU sequences form a monophyletic group and that this clade is closely related to Aschersonia. A new species of Podocrella from Costa Rica, P fusca, is described, new combinations made for P. peltata and P. harposporifera, and a key to the known species is presented.