Noah Webster's New International Dictionary of the English Language

(n.) Any grass of the genus Lolium, esp. the Lolium temulentum (bearded darnel), the grains of which have been reputed poisonous. Other species, as Lolium perenne (rye grass or ray grass), and its variety L. Italicum (Italian rye grass), are highly esteemed for pasture and for making hay.