Lolium perenne seeds mature in July.
The plant is a low-growing, tufted, hairless grass, with a bunching (or tillering) growth habit. The leaves are dark green, smooth and glossy on the lower surface, with untoothed parallel sides and prominent parallel veins on the upper surface. The leaves are folded lengthwise in bud (unlike the rolled leaves of Italian ryegrass, Lolium multiflorum) with a strong central keel, giving a flattened appearance. The ligule is very short and truncate, often difficult to see, and small white auricles grip the stem at the base of the leaf blade. Leaf sheaths at the base are usually tinged pink and hairless. Stems grow up to 90cm. It has auricles.
Lolium perenne seeds
- The inflorescence is unbranched, with spikelets on alternating sides edgeways-on to the stem. Each spikelet has only a single glume, on the side away from the stem, and between 4 and 14 Florets without awns, unlike Italian ryegrass. The anthers are pale yellow, and the plant flowers from May to November. Perennial ryegrass has a fibrous root system, with thick main roots and thinner lateral branches. Roots are usually arbuscular mycorrhizal.