Source : Webster's Revised Unabridged Dictionary (1913)

Grama grass \Gra"ma grass`\ [Sp. grama a sort of grass.] (Bot.)
   The name of several kinds of pasture grasses found in the
   Western United States, esp. the {Bouteloua oligostachya}.

Source : WordNet®

grama grass
     n : pasture grass of plains of South America and western North
         America [syn: {grama}, {gramma}, {gramma grass}]