Lolium is a genus of
tufted grasses in the
bluegrass subfamily (Pooideae).[2][3] It is often called ryegrass, but this term is sometimes used to refer to grasses in other genera.
They are characterized by bunch-like growth habits. Lolium is native to
Europe,
Asia and northern
Africa, as well as being cultivated and naturalized in
Australia, the
Americas, and various oceanic islands. Ryegrasses are naturally
diploid, with 2n=14, and are closely related to the
fescues (Festuca).[4][5][6][7]
Ryegrass should not be confused with
rye, which is a grain crop.
Lolium contains some species which are important grasses for
lawns, and as
pasture and for grazing and
hay for
livestock, being a highly nutritious stock feed. Ryegrasses are also used in
soilerosion control programs. It is the principal grazing grass in
New Zealand where some 10 million kilograms of certified seed are produced every year. There is a large range of
cultivars. The primary species found worldwide and used both for lawns and as a forage crop is
perennial ryegrass (Lolium perenne). Like many cool-season grasses of the Poaceae, it harbors a symbiotic fungal
endophyte, either Epichloë or its close relative Neotyphodium, both of which are members of the fungal family
Clavicipitaceae.[10][11]
Some species, particularly L. temulentum, are
weeds which can have a severe impact on the production of wheat and other crops. Annual ryegrass (L. rigidum) is one of the most serious and costly weeds of cropping systems in southern Australia, and
herbicide resistance is a frequent problem.[12] Ryegrass
pollen is also one of the major causes of
hay fever.
Tennis courts, including those at the
All England Lawn Tennis and Croquet Club, the venue for
Wimbledon, are planted with ryegrass.[13][14]Glyphosate-resistant Lolium has been reported from Mississippi in 2006.[15]