Plant roots can be largely divided into two basic types.

Fibrous roots are highly branched, spreading systems that can hold soil together, preventing erosion.
Taproots consist of one or a few large main roots with smaller side roots, and often serve as energy storage.

Many plant roots are covered with root hairs, single-celled extensions that increase surface area for absorption.

A single rye grass has been found to produce 7,000 miles of roots and root hairs in a four-month season.