Source : Webster's Revised Unabridged Dictionary (1913)

Blue grass \Blue" grass`\ (Bot.)
   A species of grass ({Poa compressa}) with bluish green stems,
   valuable in thin gravelly soils; wire grass.

   {Kentucky blue grass}, a species of grass ({Poa pratensis})
      which has running rootstocks and spreads rapidly. It is
      valuable as a pasture grass, as it endures both winter and
      drought better than other kinds, and is very nutritious.

Source : WordNet®

blue grass
     n : any of various grasses of the genus Poa [syn: {bluegrass}]