Flora of New Zealand Series

Italian ryegrass, Westerwolds ryegrass

Annual to biennial, slender to rather stout tufts, (20)-40-100-(130) cm; branching intravaginal, leaf-blade rolled when young. Leaf-sheath glabrous, pink at base to light brown above, not becoming very fibrous; upper sheaths sometimes scabrid. Auricles usually present, to 1.6 mm. Ligule (0.6)-1-2.5 mm, truncate, glabrous. Leaf-blade (5.5)-8-30 cm × (0.7)-2.5-9-(11) mm, abaxially glabrous and shining, adaxially smooth or usually scaberulous; margins scaberulous, tapered to scabrid acute tip. Culm 10-60 cm, erect, or spreading or decumbent, often branched below, internodes smooth. Spikes (9.5)-15-35-(45) cm, erect or curved; rachis c. 1 mm wide, usually ± scabrid. Spikelets 14-25 mm, (4)-9-14-flowered, green or purplish, overlapping, or more than their own length apart. Upper glume usually « spikelet, 5-7-nerved, narrow-lanceolate or narrow-oblong, obtuse or acute, glabrous. Lemma 6-8 mm, 5-nerved, oblong or oblong-lanceolate, smooth or minutely scaberulous especially on hyaline margins, not turgid at maturity, apex obtuse or shortly bifid; awn (2)-4-10 mm, fine, straight, subapical. Palea ≈ lemma, keels scaberulous. Anthers 3-4.5 mm. Caryopsis 2-4 × 0.5-1.5 mm.

N.: scattered; S.: occasional; St.: local; C. On roadsides and waste land, found sometimes as a weed in pasture and in gardens.

Naturalised.

An important pasture grass, indigenous to Europe, Asia and northern Africa. First recorded for N.Z. as L. italicum and known by that name until the 1930s.

Lolium multiflorum and L. perenne are very closely related. Both spp. are self-incompatible and are completely interfertile. Because they interbreed freely their separation into distinct species is often doubted and L. multiflorum regarded as a variety of L. perenne. The name L. perenne var. multiflorum was applied by Buchanan, J. T.N.Z.I. 9: 525 (1877), to plants on Kawau Id.

Westerwolds ryegrass originated in the Westerwolde area, Netherlands, as an unintentional selection of annual early-maturing plants from fields of Italian ryegrass (Terrell 1968 op. cit.). This type of Italian ryegrass is much grown in N.Z. and has been reported as naturalised, under the name L. westwolticum by Cockayne, A. H. J. Agric. N.Z. Dept Agric. 13: 212 (1916).