Abstract

Establishing the timescale of early land plant evolution is essential to testing hypotheses on the coevolution of land plants and Earth's System. Here, we establish a timescale for early land plant evolution that integrates over competing hypotheses on bryophyte-tracheophyte relationships. We estimate land plants to have emerged in a middle Cambrian-Early Ordovocian interval, and vascular plants to have emerged in the Late Ordovician-Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider a much earlier, middle Cambrian-Early Ordovician, origin.