The Middle Ordovician-early Silurian is the key period for the origin and early evolution of morphological innovations of land plants. It is widely accepted that the earliest unambiguous fossil evidence of land plants can be traced to Dapingian-Darriwilian stages of the Middle Ordovician (ca.468–463Ma), which is represented by dyads and tetrahedral tetrads from the Gondwana paleo-continent.
Click here for original story, Investigating early land plant microfossils from the lower Silurian of southern Xinjiang, China
Source: Phys.org