The causal agents of witches' broom of bamboo plants in East Asia, Epichloë 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 Epichloë species produce Ephelis-type conidia in artificial medium and are phylogenetically situated in different clades from Epichloë and Parepichloë.Here, we propose a new genus Heteroepichloë for these two bambsicolous Epichloë species.