This zone is easily distinguishable by the presence of several root hairs. Root hairs increase the absorptive surface area of the root several thousandfold and are usually less than a millimeter long. In most plants they form from asymmetric divisions of the protoderm and usually live only a few days, with old hairs farthest from the tip constantly being replaced by new ones closer to the tip. Root hairs only form in the maturing, non elongating region of the root. Because root hairs are fragile extensions of epidermal cells, they usually break off when plants are transplanted.
Primary tissues differentiate in or distally to the zone of cellular maturation.
This surrounds the root and is usually one cell thick. Epidermal cells differentiate from the protoderm and usually either lack a cuticle or have a thin cuticle that does not significantly affect water absorption. The epidermis covers all of the root except the root cap and usually has no stomata. There are two pathways in a root which can be taken in the plant for uptake of water and dissolved nutrients. Each way has its advantages and disadvantages.