Common name
Perennial Ryegrass

Derivation
Lolium L., Sp. Pl. 83 (1753); Latin name for darnel (Lolium temulentum) a weed of corn fields.

perenne- Latin for persisting for many years. Perennial.

Published in
Sp. Pl. 1: 83 (1753).

Common synonyms
Lolium perenne L. var. cristatum Pers.

Habit
Perennial, tufted. Culms erect or decumbent, slender, 24–90 cm tall. Mid-culm nodes pallid. Lateral branches simple. Leaf-sheath auricles absent, or present, falcate. Ligule an eciliate membrane. Leaf-blades 3–20 cm long, 2–6 mm wide.

Inflorescence
Inflorescence solid, a spike. Spike bilateral, 4–30 cm long, bearing 17–27 fertile spikelets on each. Rhachis semiterete, 0.9–1.7 mm wide. Spikelet packing adaxial, imbricate or approximate, 100% of their length apart, regular, 2-rowed.

Spikelets
Spikelets appressed, solitary. Fertile spikelets many flowered, comprising 4–14 fertile florets, with diminished florets at the apex, oblong, laterally compressed, 7–20 mm long, 1–7 mm wide, breaking up at maturity. Spikelets disarticulating below each fertile floret. Rhachilla internodes 1–1.7 mm long.

Glumes
Glume 1 (the lower absent or obscure), persistent, similar to fertile lemma in texture. Upper glume lanceolate or elliptic or oblong or ovate, 5–12 mm long, coriaceous, 3–7-nerved. Upper glume surface smooth. Upper glume apex obtuse.

Florets
Fertile lemma oblong, laterally compressed, 5–7 mm long, membranous or coriaceous, 5-nerved. Lemma apex obtuse, muticous. Palea membranous. Palea keels scaberulous. Apical sterile florets resembling fertile though underdeveloped. Ovary glabrous. Grain oblong, 3.8–4 mm long. Hilum linear.

Continental Distribution:
Europe, Africa, Temperate Asia, Tropical Asia, Australasia, Pacific, North America, South America, Antarctica.

Australian Distribution:
Western Australia, South Australia, Queensland, New South Wales, Victoria, Tasmania.

Western Australia: Dampier, Drummond, Dale, Menzies, Warren, Eyre, Roe, Avon. Northern Territory: Central Australia South. South Australia: Eyre Peninsula, Flinders Ranges, Northern Lofty, Murray, Yorke Peninsula, Southern Lofty, Kangaroo Island, South-eastern. Queensland: Cook, Burnett, Wide Bay, Darling Downs, Moreton. New South Wales: North Coast, Central Coast, South Coast, Northern Tablelands, Central Tablelands, Southern Tablelands, North-Western Slopes, South-Western Slopes, North-Western Plains, South-Western Plains, South Far Western Plains. Victoria: Murray Mallee, Lowan Mallee, Wimmera, Wannon, Grampians, Riverina, Midlands, Victorian Volcanic Plain, Otway Plain, Otway Range, Eastern Highlands, Gippsland Plains, Gippsland Highlands, Wilsons Promontory, Snowfields, East Gippsland. Tasmania: Furneaux Group, North West, Midlands, East Coast.

Classification. (GPWG 2001):
Pooideae

Notes
Introduced. Indigenous in parts of Europe, Asia and presumably north Africa, widely introduced and now throughout temperate regions of both hemispheres. Naturalised throughout the higher rainfall temperate areas, commonly in fields, waste places and roadsides. Flowers Aug.–Feb. Cultivated for pasture.
A variable species with numerous morphological forms.