No phylogenomic support for a Cenozoic origin of the "living fossil" Isoetes.

There is no consistent support for a Cenozoic origin of the living clade Isoetes. We obtained seemingly well-founded, yet strongly deviating, results depending on datatype and clock model. The single most important future improvement is probably to add calibration points, which requires an improved understanding of the isoetalean fossil record or alternative bases for calibration. This article is protected by copyright. All rights reserved.