grass family

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A large family of plants, the Poaceae (or Gramineae), characterized by usually hollow stems, sheath-forming leaves in two longitudinal rows, and minute flowers arranged in spikelets. The grasses include food plants such as wheat, rice, corn, barley, oats, and sorghum and also plants used for turf, fodder, and shelter.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the grasses: chiefly herbaceous but some woody plants including cereals; bamboo; reeds; sugar cane