The black henbane is sometimes referred to as the foetid nightshade, insane root, and poison-tobacco.
Photo - F. Fyles.
It is an annual or biennial plant from one to two and a half feet high. The stem is coarse, hairy, and sticky. The leaves on the stem are without stalks, oblong in general outline, with three to five pointed lobes or sometimes entire with wavy margins. The flowers, with very short stalks, are pale greenish-yellow, strongly and beautifully veined with deep purple. The seed vessel is very characteristic. It is like a deep narrow basket with a cover which opens when the seeds are ready for dispersal. The plant is in bloom from June to September.
Black henbane has become naturalized in Canada, and is found about gardens and in waste places from Nova Scotia to Ontario.
It is a well-known poisonous plant, but poisoning rarely occurs among stock on account of its strong foetid odour and rough foliage. Chesnut records the poisoning of chickens which ate the ripe seeds. Cornevin reports the poisoning of cows by eating the plant when mixed with other herbage. H. C. Long says: ' There are numbers of cases of children having been poisoned by eating the seed. The root has also caused accidents by being taken for other herbs, and the young shoots and leaves have been used in error as a vegetable. A case was reported in the press in 1910 in which twenty-five men and women visitors at a Davos pension suffered from the effects of eating the root of henbane given in error for horse-radish, or mixed with it. All suffered from strange hallucinations, but with prompt and careful treatment all had recovered in twelve hours." The poisonous principle is not destroyed by boiling or drying. Poisoning is due to one or more alkaloids, of which hyoscyamine is the chief.
The symptoms of poisoning in animals as given by Welsby are nervo-muscular exaltation, eyelids and irides much dilated, eyes amaurotic and very bright, pulse full, temperature normal, respiration difficult and hurried, profuse salivation, muscles of neck and extremities in a state of tetanic rigidity, considerable abdominal distension, stercora-ceous and renal emunctories entirely suspended, death.
Remedy and Means of Control: In the case of poisoning, professional advice should be obtained. The plants should not be allowed to mature their seed, but should be grubbed out wherever seen.