Darnel

Lolium temulentum L.

Family: Poaceae.

Names:

Lolium is from the Greek word for craft, deceitful or treacherous because Darnel was thought to be a changed form of wheat that was toxic.
Temulentum is from the Latin temulentus meaning drunk or intoxicated and refers to the symptoms experienced after eating toxic seed.
Darnel

Other names:

Bearded Ryegrass
Drake
Poison Ryegrass

Summary:

A hairless, annual grass with dark green leaves that are glossy on one side and a slender seed head with swollen seed that are wider than the stem. It is very similar to Annual Ryegrass.

Description:

Cotyledons:

One.

First leaves:

Single, strap like, parallel sided, tapering to a fine tip.

Leaves:

Emerging leaf folded flat in the bud.
Blade - Dark green, 50-400 mm long, 2-15 mm wide, flat, ribbed, parallel veins, shiny on the lower side, rough on the both sides or only on the edges. Tapers to a fine tip. Hairless.
Ligule - Membranous, flat on top, 0.5-3 mm long.
Auricles - Narrow.
Sheath - Hairless. Tubular or only slightly split.

Stems:

Single or tufted, 10-1400 mm tall, erect or low lying with the ends bending upwards, round and hollow with solid nodes. 2-4 nodes. Slightly rough near the flower head. Usually a single stem. Hairless.

Flower head:

Rigid, stiff, spike, 50-400 mm long, smooth or slightly rough, straight or slightly curved overall. Thickened, flattened and zig zag where 5-26 seed spikelets alternate up the stem.

Flowers:

Spikelets - 8-28 mm long (excluding awns) by 4-6 mm wide, oblong to wedge shaped, broad topped when in fruit, stalkless, sitting in hollows against the stem, 2-14 flowered with up to 4 empty.
Florets - Bisexual.
Glumes - Narrowly egg shaped, rounded on the back, thickened or hardened at maturity. First glume only present on the terminal floret. Second glume 7-30 mm long, equalling or longer than the spikelet, 3-11 nerved, smooth, three quarters to one and a half times the length of the spikelet.
Palea - Similar to lemma, tip translucent and keel has tiny teeth. Edges of the palea extend beyond the lemma.
Lemma - Egg shaped to oblong, 5-8.5 mm long, rounded on the back, 5-7 nerved, leathery, smooth or slightly rough. Tip is slightly 2 lobed or jagged and translucent. Variety arvense is awnless, variety temulentum has a slightly rough awn that is 3-20 mm long and attached 0.2-2 mm below the tip.
Stamens -
Anthers -
Breaks above the glumes and between the florets.

Fruit:

Grain covered with a stiff outer husk.

Seeds:

Yellow to brown. Thick, egg shaped to oblong. Surface striped, ridged and grooved.

Roots:

Large fibrous root system.

Key Characters:

Florets oblong, swollen in fruit. Grain egg shaped to oblong and usually wider than the rachis.
Rachis tends to be stouter and more zig zag than Annual Ryegrass.
Often has a red dot at the inside base of the tillers.
Emerging leaf folded flat in the bud.
Narrow auricles.
Membranous ligule.
Leaves shiny on one side.
Hairless sheath and blade.

Biology:

Life cycle:

Annual grass. Germinates autumn/winter. Flowers October-December.

Physiology:

Reproduction:

By seed.

Flowering times:

Spring in western NSW.
October to January in SA.
October to December in Perth.
Spring to summer in WA.

Seed Biology and Germination:

Little dormant seed.

Vegetative Propagules:

None.

Hybrids:

There are two varieties. Variety temulentum has awned lemmas and variety arvense is awnless.
It hybridises with other Ryegrass species, which can make positive identification difficult.

Allelopathy:

Population Dynamics and Dispersal:

Spread by seed, mainly as a contaminant of agricultural produce.

Origin and History:

South west and southern Asia. Europe. North Africa.
It has a long history as a plant that is toxic to man and was probably the Tares referred to in the Bible.

Distribution:

ACT, NSW, QLD, SA, TAS, VIC, WA.

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate. Mediterranean.

Soil:

Sandy or loamy soils.

Plant Associations:

Significance:

Beneficial:

Fodder.

Detrimental:

A weed of rotation crops, coastal islands and disturbed areas.
Very low tolerances of the seed in export wheat.

Toxicity:

Seeds may be toxic to stock and people.
Human deaths have occurred after eating bread made from grain containing Darnel seed. No cases of poisoning of stock or people has been recorded in Australia.
The toxicity is thought to be associated with a fungus.
Horses, dogs and pigs appear to be more sensitive to poisoning than the ruminants.

Symptoms:

Apathy, trembling, giddiness, uncertain gait, drunkenness, dilation of pupils, laboured breathing, nausea, vomiting, stomach pains, diarrhoea, colic, unconsciousness, paralysis and occasional death.

Treatment:

Treat symptoms.

Legislation:

Management and Control:

Because of its toxicity and low tolerance in export grains, it should be eradicated where ever it is found.

Thresholds:

Eradication strategies:

Prevent seed set for 2-3 years.
Sow clean crop seed. Apply herbicides to crops. Spray top or hay freeze pastures in infested areas.
In most situations eradication is achievable.

Herbicide resistance:

Biological Control:

Related plants:

Annual Ryegrass (Lolium rigidum) has a glume about as long as the spikelet.
Darnel (Lolium temulentum)
Italian Ryegrass (Lolium multiflorum) has it leaves rolled in the bud rather than folded and has an awn on the lemma.
Perennial Ryegrass (Lolium perenne) has a glume about half the length of the spikelet.
Stiff Ryegrass (Lolium loliaceum)

Plants of similar appearance:

Barley grass, Brome grass, Fountain grass, Guildford grass, Quaking grass, Sand fescue, Silver grass, Volunteer cereals, Wild oats, Toad rush, Winter grass.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P49.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P150. Diagrams.

Ciba Geigy (1981) Grass Weeds 2. CIBA GEIGY Ltd, Basle, Switzerland. P105. Diagrams.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.L. and Leigh, J.H. (1992). Plants of Western New South Wales. (Inkata Press, Melbourne). P114. Diagram.

Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P330.

Gardner, G.A. and Bennetts, H.W. (1956). The toxic plants of Western Australia. (West Australian Newspapers Ltd, Perth). P9-11.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P58.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #757.5.

Marchant, N.G., Wheeler, J.R., Rye, B.L., Bennett, E.M., Lander, N.S. and Macfarlane, T.D. (1987). Flora of the Perth Region. (Western Australian Herbarium, Department of Agriculture, Western Australia). P968.

Paterson, J.G. (1977). Grasses in South Western Australia. (Western Australian Department of Agriculture Bulletin 4007). P61. Diagram.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.