Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Lolium perenne L.

Perennial ryegrass, English ryegrass, Ivraie vivace, Ray-grass anglais.

Poaceae, Grass family.

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

Type: Described from Europe: ‘Habitat in Europa ad agrorum versuras solo fertili." Specimen: Anon., LINN-99.1, selected by Terrell, Techn. Bull. USDA 1392: 7 (1968). Lectotype; Van Royen s.n. Syntype: L. See also Loos and Jarvis, Bot. J. Linn. Soc. 108: 399–408 (1992), for a detailed discussion of the type.

Vegetative morphology. Plants 30–100 cm high; annual herbs, or biennial herbs, or perennial herbs; caespitose. Only fibrous roots present. Ground level or underground stems absent. Aerial stems erect, or ascending. Leaves distributed along the stems; alternate; dying annually and non-persistent. Petioles absent. Sheaths present; with the margins fused only in the lower part; glabrous (on the surface), or with trichomes (on the margins); hirsute (on the margins); sheath collars present. Ligules present; 0.4–0.6 mm long; membranous; glabrous; transversely oblong. Ligule apices truncate; erose. Leaves grass-like. Blades 10–30 mm long, (1–)2–4(–6) mm wide, appressed to the stem or spreading, folded in bud, linear, flat or folded (loosely), veins parallel, midvein similar in size to other veins in the leaf, without bulliform cells in a distinct row on either side of the midvein. Blade adaxial surface scabrous (scaberulous). Blade abaxial surface shiny (conspicuously yellow green relative to other arctic grasses), glabrous.

Reproductive morphology. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems with leaves; culm nodes not exposed. Flag leaf sheaths not inflated. Inflorescences spicate (with 5–37 spikelets); dense; linear; 3–30 cm long; 5–10 mm wide. Inflorescences main axis scabrous (rachises 0.5–2.5 mm thick at the nodes, often flexuous). Pedicels absent. Spikelets disarticulating above the glumes; obovate; 5–22 mm long; 1–7 mm wide. Florets per spikelet (2–)5–9(–10). One glume on all spikelets except the terminal spikelet, which has two. First glume (0.3–)0.5–0.75(–1.1) × spikelet length; 3.5–15 mm long; lanceolate (membranous to indurate); with trichomes; margins scabrous; veins 5; apex acuminate. Second glume 0.4–0.9 × as long as the spikelet; almost as long as, or longer than, the lowest floret; (0.3–)0.5–0.75(–1.1) mm long. Second glume lanceolate. Second glume with trichomes (scabrous); veins 5. Rachilla not pronounced between the florets; terminating in a vestigial floret; internode 1–1.5 mm long; internode scabrous. Lemma lanceolate; 3.5–9 mm long; rounded on the back; surface dull; surface sparsely scabrous; veins 5; apex acuminate; apex entire; apex scabrous; awnless (first Iqaluit collections), or awned (some cultivars). Palea well developed; 3–9.5 mm long (shorter to slightly longer than the lemmas); veins glabrous (minutely scaberulous seen at 40×). Flowers bilaterally symmetrical (zygomorphic). Perianth represented by lodicules. Stamens 3. Anthers 2–4.2 mm long. Ovary superior; carpels 3; syncarpous. Ovaries hairy (with stiff trichomes). Ovary hairs white. Styles 2. Placentation basal. Ovules per ovary 1. Fruit sessile; a caryopsis; elongate-cylindrical (3 or more times as long as wide); 3–5.5 mm long; 0.6–1.5 mm wide; indehiscent. Seeds 1.

Chromosome information. 2n = 14.

Ploidy levels recorded 2x.

Ecology and habitat. Introduced on disturbed ground in Iqaluit.

North American distribution. Arctic islands: Baffin.

General notes. This species was deliberately introduced to Baffin Island, early this century (before 2005). Along with Festuca rubra it was a major component in a mixture of grass seed that was used to hydro-seed the hillside in front of the hospital in Iqaluit. The mixture was also used in a planting on locally produced compost that was placed on the same hillside in the form of a large "C". The compost remained in position, and the "C" contains a mixture of plants of Lolium and Festuca. Seeds in the hydroseeded mixture did not remain in position at the top of the hill, or on the slope, but washed off and accumulated at the junction between the disturbed gravel and the tundra. Here they formed a lush zone of these introduced species. The occurrence of Lolium in hamlets in the Canadian Arctic Archipelago may become more widespread if hydro-seeding is used more extensively.

Ryegrass is one of the few "throw and grow" seeds that can be sown without the hassle of tilling, scarifying, or digging into the soil and destroying any of the permanent ground covers already in place. Perennial

Lolium perenne, a Eurasian species, is commercially important, being included in lawn seed mixtures as well as being used for forage and erosion prevention. Lolium perenne and L. multiflorum are interfertile and intergrade. Lolium multiflorum differs from L. perenne in being a taller, shorter lived perennial with wider leaves that are rolled, rather than folded, in the bud. Hybrids between the two species are called Lolium ×hybridum Hausskn.

Lolium multiflorum, a European species, now grows in most of North America. It is planted as a cover crop, as a temporary lawn grass, for roadside restoration, and for soil or forage enrichment; it often escapes from cultivation, becoming established in disturbed sites (Mary Barkworth, personal communication, 2006, based on E. Terrell's treatment of the genus for Flora of North America).

Illustrations. • Habitat Baffin Island. Tall green Lolium plants mixed with those of bluish Festuca rubra forms the zone of bluish grass at the junction of the disturbed gravel, and the tundra at the bottom of the hill. The gravel slope was hydro-seeded. Seeds and fertiliser appear to have travelled in run-off waters and formed the lush zone at the base. The "C" for Compost is seeded with the same mixture. There plants are about half the size. Baffin Island, Iqaluit. 19 August, 2006. Aiken 06–038 CMN. • Close-up of Lolium zone. The taller more yellow-green Lolium plants (right) are higher up the gravel hillside than the zone of bluish Festuca rubra at the junction of the disturbed gravel, and the tundra with Chamerion latifolium. Seeds and fertiliser appear to have travelled in run- off waters to this zone. The position of the two species suggest sorting by seed size in the runoff process. Baffin Island, Iqaluit. 19 August, 2006. Aiken 06–038. • Close-up of adjacent plants. Mid-green plants of Lolium and reddish plants of Festuca rubra 30–40 cm tall, growing together in the zone of successful hydro seeding. Baffin Island, Iqaluit, hillside below the hospital. 19 August, 2006. Aiken 06–038. • Close-up of plants in C for Compost. Mid-green plants of Lolium and reddish plants of Festuca rubra growing together in the zone of C for Compost. These plants were half as tall as those in the main hydro seeded zone. Baffin Island, Iqaluit, hillside below the hospital. 19 August, 2006. Aiken 06–039.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

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