Lolium is a genus of tufted grasses in the bluegrass subfamily (Pooideae). It is often called ryegrass, but this term is sometimes used to refer to grasses in other genera.

Festuca (fescue) is a genus of flowering plants belonging to the grass family Poaceae. They are evergreen or herbaceous perennial tufted grasses with a height range of 10–200 cm (4–79 in) and a cosmopolitan distribution, occurring on every continent except Antarctica. The genus is closely related to ryegrass (Lolium), and recent evidence from phylogenetic studies using DNA sequencing of plant mitochondrial DNA shows that the genus lacks monophyly. As a result, plant taxonomists have moved several species, including the forage grasses tall fescue and meadow fescue, from the genus Festuca into the genus Lolium, or alternatively into the segregate genus Schedonorus.