There are two main kinds of roots: taproots and fibrous roots. A taproot is a long, thick root that points straight down. Smaller roots can grow out of its sides. Plants with taproots include carrots and dandelions. Fibrous roots are made up of many small roots, all about the same size. The small roots grow out in many directions from the base of the stem. Grasses have fibrous root systems. A few plants can grow roots above ground. Corn, for example, may grow roots out of its lower stem. Called aerial roots, they help to prop up the plant.

The end of a root is called the root tip. It makes new cells so that the root can grow. It has a cap that protects the root as it pushes through the soil. Above the root tip, on the outside of the root, root hairs take in water and nutrients. Inside the root is the cortex. It stores the plant's extra food, which is made in the leaves and transported down to the roots. The cortex surrounds tissues that carry water and food between the roots and the rest of the plant.

Damage to the roots will harm or kill a plant. If roots or root hairs are cut, the plant may not be able to get enough nutrients. Roots that dry out may never be able to absorb water again. If the soil is packed too tightly, roots cannot grow.