An increasing problem in arable situations. Many of the rye-grasses encountered in arable weed situations may be commercial hybrids with associated high vigour. Herbicide resistance is growing.
Large, stout, fast growing and densely tufted annual or biennial 30 - 90 cm. Flower head is flattened with the spikelets arranged alternatively on opposite sides of the stem. Spikelets are awned, unlike perennial rye-grass.
Auricles: Small if present.
Leaf blade: Dark green, hairless. Leaf blade rolled in bud.