• Premise of the study: New World Bambusoideae have only recently been studied in a phylogenomic context. Plastome sequences were determined and analyzed from Arundinaria appalachiana, A. tecta, and Olyra latifolia, to refine our knowledge of their evolution and historical biogeography. A correction is noted regarding an error in an earlier report on the biogeography of Cryptochloa.• Methods: Single-end DNA libraries were prepared and sequenced on the Illumina platform. Complete plastomes were assembled and analyzed with 13 other Poaceae.• Key results: Complete sampling in Arundinaria and an additional species of Olyreae gave a more detailed picture of their evolution/historical biogeography. Phylogenomic analyses indicated that the first major divergence in Arundinaria occurred around 2.3 to 3.2 mya and that Arundinaria tecta and A. appalachiana diverged from their common ancestor around 0.57 to 0.82 mya. Estimates of the divergence of Olyra latifolia from Cryptochloa strictiflora ranged from 14.6 to 20.7 mya. The age of the stem node of Olyreae ranged from an estimated 26.9 to 38.2 mya.• Conclusions: Estimates of divergences in Arundinaria can be correlated with paleoclimatic events including an early Pliocene warming, subsequent cooling, and North American glaciations. Discriminating between alternate evolutionary/biogeographic scenarios in Olyreae is challenging.