Lecomtella madagascariensis is a monotypic grass lineage, micro-endemic to the Andringitra massif, Madagascar. Besnard et al. report a phylogenomic study and a taxonomical revision of this species. They show that it belongs to a lineage sister to three panicoid tribes of major economical importance distributed worldwide. It is also the last known member of an ancient lineage that has evolved independently for more than 20 million years and thus has a high conservation value. In addition, the study shows that next generation sequencing can be applied to rapidly generate abundant phylogenetic information, opening new avenues for plant phylogenomics.