The different types of roots are primary roots, secondary roots and tertiary roots. There are also taproots, fibrous roots and adventitious roots, the third of which are roots sent out from stems and other structures.
A plant's primary root is the first root that grows directly from the stem of the plant. The branches of this root are secondary roots, and the branches of the secondary roots are tertiary roots. If these roots are more or less the same size, the plant is considered to have a fibrous root system. Taproots are primary roots that are much bigger than the other branches. Adventitious roots may or may not penetrate the soil. Examples are the banyan tree, which has many prop roots, and epiphytes, which have aerial roots.