Abstract:The Princeton chert is one of the most completely studied permineralized floras of the Paleogene. Remains of over 30 plant taxa have been described in detail, along with a diverse assemblage of fungi that document a variety of ecological interactions with plants. As a flora of the Okanagan Highlands, the Princeton chert plants are an assemblage of higher elevation taxa of the latest early to earliest middle Eocene, with some components similar to those in the related compression floras. However, like the well-known floras of Clarno, Appian Way, the London Clay, and Messel, the Princeton chert provides an additional dimension of internal structure. In the present study, we outline the history of Princeton chert plant research, starting with Boneham and others, and extending into studies by Stockey and her students and colleagues. These studies were undertaken primarily at the University of Alberta, Edmonton. We then re-examine the individual elements of the Princeton chert flora, using the framework of the currently recognized Angiosperm Phylogeny Group (APG III) phylogeny and in light of recent fossil discoveries. We hope that this update will bring to mind new aspects of the significance of the Princeton chert flora to Paleogene paleobiology, biogeography, and plant evolution.