The causal agents of witches' broom of bamboo plants in East Asia, Epichloe bambusae and E. sasae, were morphologically and phylogenetically examined. The phylogenetic studies were conducted using ITS 1, 2, and 5.8 S rDNA regions. Both Epichloe species produce Ephelis-type conidia in artificial medium and are phylogenetically situated in different clades from Epichloe and Parepichloe. Here, we propose a new genus Heteroepichloe for these two bambsicolous Epichloe species.