The earliest well-known plant.
Arose in the Middle Silurian.
The simplest of vascular plants, an inch or so high.
Consisted of a stem, divided several times, with small spore-filled spheres at the ends of the branches.
Possibly had root hairs growing under horizontal stems.
Existed in Euramerica and Siberia until the Devonian.
Artist’s reconstruction of Cooksonia caledonica.
Image copyright © 1997 Francoise Gantet.