These drawings are helpful in learning the structure and parts of grasses and their seeds:
Gould, Frank W. Grasses of Southwestern United States. 1973. The University of Arizona Press: Tucson, Arizona.
This informational sheet helps identify grass seeds from the family Poaceae (old family name was Gramineae):
Martin, Alexander C and William D Barkley. Seed Identification Manual. 2000. The Blackburn Press: Caldwell, New Jersey.