The purple cockle is also popularly known as corn cockle, corn rose, and corn campion.
Agrostemma means "the-crown-of-the-field." The richly coloured flowers waving among the ears of grain deserve the name, but its aptitude is lost, no doubt, upon the busy farmer who sees only a certain loss to his crop. It is a tall annual or biennial introduced from Europe, one to three feet high, more or less covered with silky hairs. The leaves are two to five inches long, narrow, pointed, with entire margins. The flowers are purple, pale towards the centre, with dark markings, from one to two inches wide. The petals are five, shorter than the long, narrow, pointed, and hairy sepals. The seeds are about 1|8 inch in diameter, black or of such deep purple as to appear black, rough, with rows of short, close teeth. The plant is in flower from July to August.
Purple cockle was introduced into Canada from Europe, and is now scattered throughout the country in grain fields and along roadsides.
This weed, containing saponin, is poisonous both to animals and human beings. The seeds are most harmful. The seed capsules, being on a level with the heads of grain, and ripening at the same time, are cut and milled with the grain. Unless the wheat is very carefully screened, the flour is rendered unwholesome. The presence of the poison may be detected in lower grades of flour by its pecular odour, and even by remnants of the rough, black, seed-coat. Very dangerous results may follow the repeated use of even a small quantity of this flour, as it will produce a chronic disease known as "githagism."
The symptoms of chronic poisoning are: gradual depression, headache, nausea, diarrhoea, burning of the skin, loss of vigour in muscular movements and breathing, sometimes followed by coma and death.
Cornevin describes the symptoms in the acute form in the case of horses, cattle, and pigs. In the horse, if a small quantity only is taken, there is yawning, heavy colic, stamping and evacuation of rather soft faeces. If larger quantities are taken, the symptoms, which commence in about an hour, are salivation, frequent yawning and turning of the head, colic, pale mucus, hurried and weak pulse, rise in temperature, and accelerated respiration. Some time later there are muscular tremors succeeded by pronounced rigidity, and the fasces are diarrhoeic and foetid. The animal lie-down, and getting up is painful; it falls into a kind of coma, stretches itself to the utmost, and death takes place without convulsions.
In cattle, the symptons observed one hour after eating are restlessness, salivation, and grinding of the teeth. Excitement and colic are followed sometimes by coughing, this state lasting from five to eight hours. There is then a period of coma, characterized by permanent decubitus, repeated foetid diarrhoea, hurried and plaintive respiration, accelerated and gradually weakening pulse, a gradual loss of motor and sensory powers, and a progressive decline in temperature. Death occurs in twenty-four hours.
In the case of pigs, the animal grunts, lies down and remains thus, with its snout embedded in the straw. There is vomiting, more or less violent colic and diarrhoea, the evacuation consisting of bad-smelling, spumous faecal matter. At times there are clonic contractions. Young pigs are most susceptible. (H. C. Long.)
Remedy and Means of Control: Weed out corn cockle before or not later than the first appearance of the purple flowers. Badly infested areas may be sprayed with copper or iron sulphate when the plants are in bloom to prevent the production of seeds.