plural of ryegrass

(countable) Any of several species of tufted grasses of the genus Lolium. / (uncountable) A collection of plants of any of the species, as in a lawn or field.

plural of annual ryegrass

(US, UK, Canada) Lolium multiflorum, grown as a cover crop / (Australia) Lolium rigidum which considered a noxious weed in Australia