Silurian
The first fossil records of vascular plants, appeared in the second half of the Silurian period. The earliest known representatives of this group are the Cooksonia (mostly from the northern hemisphere) and Baragwanathia (from Australia). A primitive Silurian land plant with xylem and phloem but no differentiation in root, stem or leaf, was much-branched Psilophyton. This plant reproduced by spores and respired through stomata on every surface, and probably photosynthesized in every tissue exposed to light.