The first terrestrial plants were Paleozoic whisk ferns such as Rhynia and Psilophyton, and they emerged at the beginning of the Devonian Period, 400 million years ago.
These plants are leafless, similar to present-day whisk ferns. Rhizomes spread out from its sides, and stems grow straight up from them. The stems branch out into Y-shapes and their tips have sporangia (sacks filled with spores).