Genus: Lolium 

Life > eukaryotes > Archaeoplastida > Chloroplastida > Charophyta > Streptophytina > Plantae (land plants) > Tracheophyta (vascular plants) > Euphyllophyta > Lignophyta (woody plants) > Spermatophyta (seed plants) > Angiospermae (flowering plants) > Monocotyledons > Order: Poales > Family: Poaceae

There are four species worldwide (tropical Africa, USA), all of which are naturalised in southern Africa (northern Namibia, Botswana). 

Species naturalised in southern Africa

List from Plants of Southern Africa - an Online Checklist (SANBI) and Flora of Zimbabwe.

Lolium multiflorum (Italian ryegrass, Westerworlds ryegrass)
Lolium perenne (Perennial ryegrass)
Lolium rigidum
Lolium temulentum (Darnel)