14.05 LOLIUM L.
Edward E. Terrell

Plants annual or perennial; cespitose, sometimes shortly rhizomatous. Culms 10–150 cm, slender to stout, erect to decumbent, rarely prostrate. Sheaths open, rounded, glabrous, sometimes scabrous; ligules to 4 mm, membranous, glabrous; auricles sometimes present; blades flat, linear. Inflorescences distichou. Spikes, with solitary spikelets oriented radial to the rachises, perpendicular to the rachis concavities. Spikelets laterally compressed, with 2–22 florets, distal florets reduced; rachillas glabrous; disarticulation above the glumes, beneath the florets. Glumes usually 1, 2 in the terminal spikelets, lanceolate to oblong, rounded over the midvein, membranous to indurate, 3–9-veined, unawned; lower glumes absent from all but the terminal spikelet; upper glumes from shorter than to exceeding the distal florets; calluses short, blunt, glabrous; lemmas lanceolate, ovate or oblong, rounded over the midvein, membranous, chartaceous, 3–7-veined, apices sometimes hyaline, unawned or awned, awns subterminal, more or less straight; paleas membranous, usually smooth, keels ciliolate; lodicules 2, free, lanceolate to ovate; anthers 3; ovaries glabrous. Caryopses dorsally compressed, oblong, broadly elliptic or ovate, longitudinally sulcate; hila linear, in the furrow; embryos 1/5–1/3 as long as the caryopses. x = 7. Lolium, first mentioned in Virgil’s Georgics, is an old Latin name for darnel, Lolium temulentum.

As interpreted here, Lolium comprises five species that are native to Europe, temperate Asia, and northern Africa. All have been introduced to the Flora region, often as forage grasses; most have become established.

Lolium used to be included in the Triticeae, but evidence from genetics, morphology, and other studies shows its closest relationship to be to the species included here in Schedonorus. Artificial hybrids have been produced among L. perenne, L. multiflorum, Schedonorus pratensis, and S. arundinaceus. Cultivars of these crosses have been registered for commercial use and are sometimes used for forage. Natural hybrids are not uncommon in Europe.

SELECTED REFERENCES Aiken, S.G., M.J. Dallwitz, C.L. McJannet, and L.L. Consaul. 1997. Fescue Grasses of North America: Interactive Identification and Information Retrieval. DELTA, CSIRO Division of Entomology, Canberra, Australia. CD-ROM; Dannhardt, G. and L. Steindl. 1985. Alkaloids of Lolium temulentum: Isolation, identification and pharmacological activity. Pl. Med. (Stuttgart) 1985:212–214; Dore, W.G. 1950. Persian darnel in Canada. Sci. Agric. (Ottawa) 30:157–164; Soreng, R.J. and E.E. Terrell. 1997 [publication date 1998]. Taxonomic notes on Schedonorus, a segregate genus from Festuca or Lolium, with a new nothogenus, ×Schedololium, and new combinations. Phytologia 83:85–88; Terrell, E.E. 1968. A Taxonomic Revision of the Genus Lolium. Technical Bulletin, United States Department of Agriculture No. 1392. U.S. Government Printing Office, Washington, D.C., U.S.A. 65 pp.

The interactive dichotomous key and interactive multientry key are currently not available.

1.Plants either long-lived perennials with 2–10 florets per spikelet, or annuals or short-lived perennials with 10–22 florets per spikelet ... 2
1.Plants annuals, with 2–10(11) florets per spikelet ... 3
2.Plants long-lived perennials, with 2–10 florets per spikelet; lemmas unawned or awned, awns to about 8 mm long ... L. perenne
2.Plants annuals or short-lived perennials, with 10–22 florets per spikelet; lemmas usually awned, awns to 15 mm long, rarely unawned ... L. multiflorum
3. Spikelets somewhat sunken in the rachises and partly concealed by the glumes ... L. rigidum
3. Spikelets not sunken in the rachises and not concealed by the glumes ... 4
4. Lemmas 3.5–8.5 mm long; paleas from 1.2 mm shorter than to 0.8 mm longer than the lemmas; mature florets and caryopses 2–3 times longer than wide ... L. temulentum
4. Lemmas (5.2)7–12 mm long; paleas usually 0.5–1.8 mm longer than the lemmas; mature florets and caryopses 3.7–5 times longer than wide ... L. persicum

 

1. Lolium perenne L.
Perennial Ryegrass, English Ryegrass, Ivraie Vivace, Ray-Grass Anglais

Plants long-lived perennials. Culms to 100 cm. Leaves folded in the bud; blades usually 10–30 cm long, (1)2–4(6) mm wide. Spikes 3–30 cm, with 5–37 spikelets; rachises 0.5–2.5 mm thick at the nodes, often flexuous. Spikelets 5–22 mm long, 1–7 mm wide, with (2)5–9(10) florets. Glumes 3.5–15 mm, (1/3)1/2–3/4 as long as to slightly exceeding the distal florets, membranous to indurate; lemmas 3.5–9 mm long, 0.8–2 mm wide, unawned or awned, awns to about 8 mm, attached 0.2–0.7 mm below the apices; paleas shorter than to slightly longer than the lemmas; anthers 2–4.2 mm. Caryopses 3–5.5 mm long, 0.7–1.5 mm wide, 3 or more times longer than wide. 2n = 14.

Lolium perenne, a Eurasian species, is now established in disturbed areas throughout much of the Flora region. It is commercially important, being included in lawn seed mixtures as well as being used for forage and erosion prevention.

Lolium perenne intergrades and is interfertile with L. multiflorum; it also intergrades with L. rigidum. Typical L. perenne differs from L. multiflorum in being a shorter, longer-lived perennial with narrower leaves that are folded, rather than rolled, in the bud. Hybrids between the two species are called Lolium ×hybridum Hausskn.

 

2. Lolium multiflorum Lam.
Annual Ryegrass, Italian Ryegrass, Ivraie Multiflore, Ray-Grass d’Italie

Plants annuals or short-lived perennials. Culms to 150 cm. Leaves rolled in the bud; blades usually 10–30 cm long, (2)3–8 (13) mm wide. Spikes 15–45 cm, with 5–38 spikelets; rachises 0.8–2 mm thick at the nodes, not flexuous. Spikelets 8–31 mm long, 2–10 mm wide, with (10)11–22 florets. Glumes 5–18 mm, 1/4–1/2 as long as the florets, membranous to indurate; lemmas 4–8.2 mm long, 1–2 mm wide, usually awned, awns to 15 mm, attached 0.2–0.7 mm below the apices, rarely unawned; paleas shorter than to slightly longer than the lemmas; anthers (2.5)3–4.5(5) mm. Caryopses 2.5–4 mm long, 0.7–1.5 mm wide, 3 or more times longer than wide. 2n = 14.

Lolium multiflorum, a European species, now grows in most of the Flora region. 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.

Lolium multiflorum and L. perenne are interfertile and intergrade. Lolium multiflorum differs from L. perenne in being a taller, shorter-lived perennial or annual with wider leaves that are rolled, rather than folded, in the bud. Hybrids between the two species are called Lolium ×hybridum Hausskn. Lolium multiflorum also hybridizes with L. rigidum; those hybrids are called Lolium ×hubbardii Jansen & Wacht. ex B.K. Simon.

 

3. Lolium rigidum Gaudin
Stiff Ryegrass

Plants annual. Culms to 70 cm. Blades to 17 cm long, 0.5–5(8) mm wide. Spikes 3–30 cm, with 2–20 spikelets; rachises 0.5–3.5 mm thick at the nodes, with the spikelets somewhat sunken in the rachises and partly con-cealed by the glumes. Spikelets 5–18 mm long, 1–3(7) mm wide, with 2–8(11) florets. Glumes 4–20(30) mm, usually from 3/4 as long as to slightly exceeding the distal florets, rather indurate; lemmas 3–8.5(10.5) mm long, 0.9–2 mm wide; paleas slightly shorter than to slightly longer than the lemmas, usually unawned, sometimes awned, awns to 10 mm; anthers 1.2–3.2 mm. Caryopses 2.7–5.5 mm long, 1–1.5 mm wide, 3 or more times longer than wide. 2n = 14.

Lolium rigidum is native to Europe, North Africa, and western Asia. It has been found as a weed of roadsides and waste places at scattered locations in the contiguous United States and Canada.

Lolium rigidum intergrades with L. perenne, L. multiflorum, and, occasionally, L. temulentum. Hybrids with L. multiflorum are called Lolium ×hubbardii Jansen & Wacht. ex B.K. Simon.

 

4. Lolium temulentum L.

Plants annual. Culms to 120 cm. Blades to 27 cm long, 1–12 mm wide. Spikes 2–40 cm, with 3–26 spikelets; rachises 0.5–3.5 mm thick at the nodes, spikelets not sunken in the rachises, not concealed by the glumes. Spikelets 5–28 mm long, 1–8 mm wide, with 2–10 florets. Glumes 5–28 mm, membranous to indurate; lemmas 3.5–8.5 mm long, 1.2–3 mm wide, unawned or awned, awns to 23 mm, attached 0.2–2 mm below the apices; paleas 1.2 mm shorter than to 0.8 mm longer than the lemmas, often wrinkled; anthers 1.5–4 mm. Caryopses 3.2–7 mm long, 1–3 mm wide, 2–3 times longer than wide, turgid. 2n = 14.

Lolium temulentum is said to be the tares of the Bible. Its two subspecies differ mainly in quantitative characters.

1. Lemmas 3.5–5.5 mm long, 1.2–1.8 mm wide; glumes 5–16 mm long; caryopses 3.2–4.5 mm long, 1.2–1.8 mm wide; rachises slender ... subsp. remotum
1. Lemmas 4.5–8.5 mm long, 1.5–3 mm wide; glumes (5.5)7–28 mm long; caryopses (3.8)4–7 mm long, (1)1.5–3 mm wide; rachises rather stout ... subsp. temulentum

 

Lolium temulentum subsp. remotum (Schrank) Á. Löve & D. Löve
Flax Darnel, Ivraie du Lin

Blades 1–6.5 mm wide. Spikes 2–23 cm, with 3–20 spikelets; rachises slender. Spikelets 5–16 mm long, 1–5 mm wide. Glumes 5–16 mm, (1/2)2/3 as long as to somewhat exceeding the distal florets; lemmas 3.5–5.5 mm long, 1.2–1.8 mm wide, usually unawned, rarely awned, awns to 10 mm, attached 0.2–1 mm below the apices. Caryopses 3.2–4.5 mm long, 1.2–1.8 mm wide.

Lolium temulentum subsp. remotum is native to Europe, Asia, and northern Africa. It originated as a weed in flax fields, through unintentional selection for seeds that could not be separated from flax seed using early harvesting techniques. It is a rare weed in the Flora region, being reported only from southern Ontario and California, where it grows in waste places and fields.

 

Lolium temulentum L. subsp. temulentum L.
Darnel, Ivraie Enivrante

Blades (1.5)3–10(12) mm wide. Spikes 5–40 cm, with 5–26 spikelets; rachises rather stout. Spikelets 8–28 mm long, 3–8 mm wide. Glumes (5.5)7–28 mm, from 3/4 as long as to longer than the florets, somewhat indurate; lemmas 4.5–8.5 mm long, 1.5–3 mm wide, unawned or awned, awns to 23 mm, attached 0.5–2 mm below the apices. Caryopses (3.8)4–7 mm long, (1)1.5–3 mm wide.

Lolium temulentum subsp. temulentum is found occasionally in disturbed sites throughout much of the Flora region. It is native to the Eastern Hemisphere, where it is known only as a weed, especially of grain fields. Awn presence or absence and length vary, and have no taxonomic significance.

The seeds sometimes become infected with an endophytic fungus, assumed to be the source of the toxic pyrrolizidine alkaloids loline, 6-methyl loline, and lolinine, but not temuline, which is now considered an artifact of isolation (Dannhardt and Steindl 1985). Because primitive agricultural practices could not separate seeds of Lolium temulentum from those of wheat, infected seeds often resulted in poisonous flour.

 

5. Lolium persicum Boiss. & Hohen.
Persian Darnel

Plants annual. Culms 14–45(60) cm. Blades 3.5–20 cm long, 1.5–7 mm wide. Spikes 3–21 cm, with 3–12 spikelets; rachises 0.5–2 mm thick at the nodes, often flexuous, spikelets not sunken in the rachises, not concealed by the glumes. Spikelets 9–27 mm long, 1.5–7 mm wide, with 4–9 florets. Glumes (4.7)7.5–23 mm, from 2/3 as long as to equaling the distal florets, somewhat indurate; lemmas (5.2)7–12 mm long, 1.5–2.7 mm wide, awns (1.5)5–18 mm, attached 0.2–1 mm below the apices; paleas usually 0.5–1.8 mm longer than the lemmas; anthers 1.5–3 mm. Caryopses 4.8–7 mm long, 1.2–2 mm wide, 3.7–5 times longer than wide. 2n = 14.

Lolium persicum, a native of southwest Asia, has been found as a weed in grain fields and waste places in southern Canada, Montana, North Dakota, and Wyoming and, as an adventive, in New York and Missouri. It is now one of the top ten weeds of western Canadian cereal crops. It first became established in North America in Cavalier County, North Dakota, prior to 1910 (Dore 1950).