Secale cereale L.
Secale is the Latin name for Rye.
Cereale is Latin for cereal.
Other NamesCereal Rye
Summary:An erect, several stemmed cereal plant to 1.5 m tall with a bearded, compact, 2 row seed head that droops with age.
Leaves:Emerging leaf rolled in the bud.
Blade - Rough to touch, flat. Hairless. 75-300 mm long x 10-20 mm wide.
Ligule - Membranous rim, 1 mm long. Flat on top.
Auricles - Small.
Sheath - Hairless. Rolled and overlapping. Prominent veins.
Collar - Prominent and lighter. Hairless.
Stems: Erect, slender, 200-1500 mm tall. Hairless or hairy below the seed head. Usually has a waxy bloom. Tillers vigorously with usually less than 10 stems arising from the base.
Flower head:Bearded, dense cylindrical spike. 70-150 mm long. Erect initially and drooping with age. Awned.
Flowers: Spikelets - No stalk, flattened. Single and overlapping in a row on opposite sides and pressed against a zigzag stem. Strongly attached to the stem. 2 fertile florets per spikelet.
Florets - Bisexual.
Glumes - 2 the same size and shape, awl shaped, 7-10 mm long, 1 rib, keeled, flattened, rough to touch.
Palea - 12-15 mm long, narrow, no awns, 2 lobes, 2 keels.
Lemma - Sticks out from the glumes, oblong to narrowly egg shaped, 12-15 mm long, stiff, 5 ribs, flattened. Hairy or finely toothed on the keel and edges. Keel tapers to a long straight awn about 20 mm long.
Light to dark brown. Oblong to oval or wedge shaped, 5-7 mm long x 2-3 mm wide. Almost circular in cross section. Surface grooved, wrinkled and hairless. Easily rubbed from the husks.
Key Characters:Inflorescence a dense cylindric spike and not enclosed in the leaf sheath.
Spikelets, subtended by 2 glumes, solitary at each node of the rachis, not digitate, sessile, erect with 2 (rarely 3) bisexual florets, breaks above the more or less persistent glumes.
Lemmas 2, awned, 5 ribbed.
Adapted from J.M. Black, T.D. Macfarlane and E.M. Bennett.
Annual. Seeds germinate from autumn to spring with a flush in autumn. Flowers July to October.
Physiology:Tolerant of acid soils.
Flowering times:August in SA.
July to October in Perth.
Spring and summer in WA.
Seed Biology and Germination:Vegetative Propagules:
Hybrids:This species derived from the perennial Secale (Secale montanum).
Sterile hybrids are often used for binding sand on construction sites.
Allelopathy:Stubble may reduce the germination and growth of plants in the following season.
Population Dynamics and Dispersal:Spread by seed. Most spread is by intentional planting and naturalisation by persistence in or close to these areas.
Origin and History:Europe.
Introduced as a cultivated crop.
Distribution:NSW, SA, TAS, VIC, WA.
Courtesy Australia's Virtual Herbarium.
Temperate regions. Mediterranean.
Soil:Most abundant on sandy and acid soils.
Cereal crop used for stock feed and making Rye bread.
A sterile hybrid is often used as a binder in sandy soils.
Detrimental:Weed of other crops.
Toxicity:Cereal Rye may be infected with a fungus Ergot (Claviceps purpurea) which produces alkaloids similar to the psychotomimetic drug LSD. Two types of Sweet Scabious intoxication have been reported; gangrenous ergotism, from consuming small amount over a long period and convulsive ergotism which affect both people and animals.
Grain with 3 ergots per 1000 kernels can be toxic.
Symptoms:Gangrenous ergotism of man and cattle; blockage of circulation to the extremities, tingling in the fingers, vomiting, diarrhoea, gangrene of the toes and fingers, ulceration of the mouth. It is a dry form of gangrene and limbs may fall off. In cattle there is lameness, especially in the hindquarters, gangrene of feet, ears and tail. Pregnant cows may abort. There is a characteristic band where the gangrenous tissue ends.
Convulsive ergotism; symptoms similar to those of gangrenous ergotism and are followed by painful spasms of the limbs, epileptic convulsions and delirium in man. Cattle become excitable and run with a swaying uncoordinated gait.
Legislation:Management and Control:
A number of selective herbicides are available for control of Rye in following broad leaf crops.
Thresholds:5-20 plants per m-2 are usually worth controlling in broadleaf crops.
Eradication strategies:Prevent seed set.
Cultivation, mowing or application of herbicides before flowering for a few years usually results in eradication. In many cases it disappears naturally without intervention.
Herbicide resistance:Biological Control:
Related plants:Secale (Secale montanum)
Triticale (Triticum aestivum x Secale cereale).
Plants of similar appearance:Barley (Hordeum vulgare) has one bisexual floret in the spikelet.
Wheat (Triticum aestivum) has a many ribbed lemma, and larger auricles.
References:Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P142. Diagram.
Everist, S.L. (1974). Poisonous Plants of Australia. (Angus and Robertson, Sydney). P802.
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). P68. Photo.
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). #1118.1.
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). P985.
Moerkerk, M.R. and Barnett A.G. (1998) More Crop Weeds. (R.G and F.J. Richardson, Melbourne). P41. Photos. Diagrams.
Paterson, J.G. (1977). Grasses in South Western Australia. (Western Australian Department of Agriculture Bulletin 4007). P83. Diagrams.
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