Land plants: Making their mark
During this early period of evolution in the segmented animals, plant were also evolving, with the development of rooting systems which were absent in the mosses. Rooting systems permitted water sources below the ground to be utilized. Consequently root development permitted plants to survive in less moist environments. Three groups of plants, all of which have living descendants evolved root structures (club mosses Lycopodium, horsetailsSphenophyta and ferns Pterophyta) and possessed within their stems strong woody vessels for the transport of water absorbed by the roots. Such adaptations provided the structural rigidity for some of these plants to grow big (up to 30 m) and created the first true forests.