Clover, ferns and willow trees are just a few examples of vascular plants. Vascular plants, also known as "tracheophytes" or higher plants, utilize lignified tissues that transport water and nutrients internally throughout the plant. Vascular plants also include a number of flowering plants and tracheids.
Structures known as "xylem" are hard-walled tubes comprised of lignified tissues that serve to transport moisture throughout the plant. Other structures, known as "phloem," are used to transport the nutrients needed to maintain cellular metabolic function. The fossilized remains of the earliest vascular plants have been dated back to the Silurian period, about 410 million years ago.