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The roots that evolved in vascular plants enabled them to obtain water and nutrients from the soil and provided a mechanical anchor for plants capable of growing tall. As in the case of leaves and wood, the fossil record shows that the first vascular plants lacked roots. These plants survived only in extremely wet environments in which they could absorb water through horizontal, and possibly submerged, stems. The evolution of roots allowed vascular plants to expand into drier habitats and ensured the stability of taller stems.

The fossil record also indicates that roots evolved at least twice. Nevertheless, the roots of all vascular plants share many features. This suggests that the physical challenges of growing through dense soil and the demands of obtaining water and nutrients from that soil place strong constraints on root structure.