Treubiomyces pulcherrimusresemblesChaetothyrium, type of the family Chaetothyriaceae, in the following characters: a pale superficial mycelium appressed to the cuticle of living plants; a globoid ascoma developing beneath a mycelial shield, with which the ascoma is fused in the apical region; a centrum composed of a basal fascicle of aparaphysate asci; a palisade of short periphysoids projecting downward from the roof of the locule to the tips of the asci; and a schizogenous, periphysate ostiole. The asci have a conspicuous refractive ring in the thickened wall at the apex. Ascospores are discharged forcibly, but dehiscence of the presumed bitunicate asci could not be demonstrated. Mycelial cultures were obtained from ascospores discharged onto agar plates. No conidia were found in culture or field material.