What is "cuba grass"

Johnson grass \John"son grass`\ [Named after W. Johnson of Alabama, who planted it about 1840-1845.] (Bot.) A tall perennial grass ( Sorghum Halepense), valuable in the Southern and Western States for pasture and hay. The rootstocks are large and juicy and are eagerly sought by swine. Called also Cuba grass, Means grass, Evergreen millet, and Arabian millet.