grass - narrow-leaved green herbage: grown as lawns; used as pasture for grazing animals; cut and dried as hay

Elymus, genus Elymus - tall tufted perennial grasses (such as lyme grass or wild rye)

Canada wild rye, Elymus canadensis - North American wild rye

Elymus caput-medusae, medusa's head - weedy rye grass having long bristling awns