The new genus Coniarthonia is described to accommodate a group of species previously placed in Anhonia and Arthotheliwn. Crystallized red pigments that are distributed throughout hydrophobic ascomatal structures are characteristic of the new genus, which includes species with both muriform and transversely septate ascospores. Coniarthonia erythrocarpa, C. gregarina, C. pulchernma, C. pyrrhula and C. ivilmsiana are new combinations, and C. haematodea is new to science. Two subgroups are distinguished in the genus: the C. pyrrhula group, with larger ascospores, and the C. pulckcrruna group, which has comparatively small, one-septate ascospores. The reddish compounds are characterized by TLC. A key to the species is provided.