Most grasses are annual or perennial herbs with fibrous roots and, often, rhizomes.
The stems are always noded and are typically hollow and swollen at the nodes, although many genera have solid stems. The flowers are of a unique form, the inflorescence being subdivided into spikelets each containing one or more tiny florets. The dry seedlike fruit is called a caryopsis, or grain. Economically the grass family is of far greater importance than any other. The cereal grasses, e.g., wheat , rice , corn , oats , barley , and rye , provide the grain that is the staple food of most of mankind and the major type of feed.