Word Study
nut grass
CIDE DICTIONARY
nut grass, n.
A widely distributed perennial plant of the Sedge family (Cyperus rotundus , var. Hydra ), which has slender rootstocks bearing small, edible, nutlike tubers, by which the plant multiplies exceedingly, especially in cotton fields. [1913 Webster]
For further exploring for "nut grass" in Webster Dictionary Online