POISONOUS PLANTS IN NEW ZEALAND

New Zealand Journal of Agriculture, Volume 82, Issue 6, 15 June 1951, Page 511

POISONOUS PLANTS IN NEW ZEALAND

this is the ninth section of a series of descriptions of poisonous plants which grow in

New Zealand by

H. E. Connor,

, Botanist, Department of Scientific and Industrial

Research, Wellington. The series is appearing monthly in the "Journal", and glossaries to be used with the series were published with the first section, which appeared in the October, 1950, issue.

DICOTYLEDONS

Solanaceae African Boxthorn. Lyclum ferocissimum Miers. (Fig. 19, B) Botanical description: Habit—densely and stoutly branched, spinebearing shrub up to 3ft. or more tall. Leaves Subsessile, spathulate-oblong, glabrous, about fin. long. Flowers — Small, whitish, with slender corolla tube. Fruit— Globular, scarlet berries. (South Africa.) Habitat: Hedge plant. Distribution: Sparingly naturalised in several localities in both islands. General: In New Zealand instances of boxthorn poisoning in poultry have occurred when the leaves were eaten. African boxthorn has been suspected of poisoning pigs in Australia. The related Chinese boxthorn, L. chinense Mill., which has longer leaves and few to no prickles, occurs as a garden escape and has become established in waste places in both islands. There is no evidence other than close relationship to African boxthorn for suspecting Chinese boxthorn as a poisonous plant. Poisonous principle: Not known.

Bittersweet. Solanum dulcamara L. (Fig. 19, A) Botanical description: Habit More or less pubescent or sometimes glabrous, shrubby climber with stems 4 to 6ft. long. Leaves — or sometimes 3 to 5 parted, 1 to 3in. long, the entire ones cordate or ovate-cordate, or the upper ones hastate. Flowers Many, in drooping panicled corymbs opposite the leaves; corolla white or violet, 4 in. in diameter. Fruit— Ovoid, red or rarely yellowish green berry. (Europe.) Habitat: Scrambles through hedges; may form thickets. Distribution: A few swampy areas in both islands; cultivated in gardens. General: The distribution of bittersweet is not great in New Zealand at present, which probably accounts for the absence of known plant poisonings. Bittersweet is recognised as a poisonous plant, as horses, sheep, and cattle have occasionally been poisoned by eating it. A somewhat disagreeable odour given off from the crushed leaves should persuade stock to leave the plant ungrazed. Leaves, stems, and berries are poisonous, as all parts of the plant contain the toxin. Symptoms of poisoning are headache, nausea, emesis, and gastritis. Larger doses produce central nervous paralysis and even heart disturbances. Local irritation and haemoglobinuria may also occur. . Poisonous principles: The colloidal alkaloidal glycoside solanine, which can be hydrolysed under acid conditions to the more readily absorbable solanidine, is present throughout the plant. Solaceine has been recorded for bittersweet, and this is also hydrolysable under acid conditions to solanidine.

Jerusalem Cherry. Solanum pseudocapsicum L. (Fig. 19, C) Botanical description: Habit — branching shrub up to 3ft. tall. Leaves— oblong to oblanceolate, about 3in. long, obtuse to subacute, wavy, glabrous. Flowers— Solitary or few together, white, about jin. in diameter. Globular, scarlet berries about Jin. in diameter, remaining for a long time on the plant. (Tropical America.) Habitat: Damaged forest.

Distribution: Occasional to locally plentiful in several localities in North Island. Often cultivated. General: Jerusalem cherry has not been responsible for any known poisonings among stock in New Zealand but has been suspected of poisoning cattle in Australia. The fruits have been responsible for deaths and sickness in human beings. Because of the presence of toxic alkaloids in the plant, poisonings could occur if quantities of it were ingested. Poisonous principle: The alkaloid solanocapsine is present throughout the

plant. This alkaloid causes irritation and has a direct slowing effect on the heart.

Potatoes. Solanum tuberosum L. (Fig. 20) General: Sprouted or greened potatoes have long been recognised as dangerous fodder for stock consumption, cattle, horses, and poultry having been ; poisoned as a result of eating potatoes in this condition. The green haulms of the potato plant are also known to produce deleterious effects on cattle which have eaten them; decaying or ensiled haulms appear to be fed with no ill effects. Potatoes which have not been properly earthed up may become greened through exposure to sunlight; the resultant crop is then poisonous to man, as has been shown in New Zealand and other parts of the world. Raw potato peelings have been responsible for sickness and, possibly in one case, death. An inflammatory condition of the skin, termed potato eruption, is reported in pigs, cattle, and horses which have eaten large quantities of raw or cooked potato tubers or leaves, or kitchen refuse which included potatoes in either form. According to the authors, this condition is more prevalent in spring. The causal agent of potato eruption is incompletely understood. The quantity necessary to produce the condition varies with the class of stock and the time of the year. This condition is not known to occur in New Zealand. Symptoms of poisoning: Symptoms in pigs are not diagnostic; they include marked dullness, copious diarrhoea, and regurgitation of stomach contents. Cattle show weakness, dilation of the pupils, trembling, and frothing at the mouth, followed by death. Affected human beings suffer from headache, nausea, emesis, gastritis, and, if large doses have been absorbed, nephritis, haemoglobinuria, and central nervous paralysis. The toxin also has a local irritant action and could cause gastroenteritis. Potato eruption is accompanied by rise in temperature, loss of appetite, retarded defaecation, salivation, and weeping, which precede the vesicular inflammation of the skin of the lower parts of the limbs. Rupture of the vesicles produces a moist, red surface. In a few days crusts are formed on the ruptured surface. Prolonged feeding increases the size of the affected area; ulceration may set in. Severe diarrhoea and weakness may be associated symptoms. Death may follow. Gastroenteritis is a post-mortem examination symptom. Poisonous principle: The toxin present in greened and sprouting potatoes is solanine, a glycosidal alkaloid. (See also Solanum dulcamara on preceding page.) CHANGES OF ADDRESS OF “JOURNAL” SUBSCRIBERS To ensure continuity of delivery of issues of “The New Zealand Journal of Agriculture”, subscribers are required to give 4 weeks’ notice of change of address. The old address (preferably an address label clipped from a recent “Journal” envelope or wrapper) and the new address should be sent to the nearest office of the Department of Agriculture.