Other popular names given to this Ranunculus are biting crowfoot, celery-leaved crowfoot, blisterwort, and among its French names are Mort au vaches, Herbe sardonique.
The cursed crowfoot is a stout, hollow-stemmed annual from six inches to two feet high. The leaves from the root are thick, with long and broad stalks, rounded or heart-shaped, three lobed and toothed. The upper leaves have very short stalks or none at all, longer lobes and fewer teeth. The flowers are pale yellow, small, about one-quarter of an inch broad, the petals about the same length as the sepals. The fruiting heads or clusters of seeds, which may be seen on plants still in flower, are oblong or cylindric. The plants are in bloom from June to August, sometimes earlier or later, according to locality and climatic conditions.
It is found in wet ditches, low lands, and swamps from New Brunswick to British Columbia.
As its name implies, the cursed crowfoot is one of the most virulent of our native species. It contains very acrid and poisonous principles. Any small portion of the leaf or flower, if eaten, will cause severe pain and serious inflammation, and if applied to the skin will raise painful blisters in a short time. Beggars in Europe use this and other species of buttercup to produce running sores. An old herbalist says, "Cunning beggars doe use to stampe the leaves, and lay it unto their legs and armes, which causeth such filthy ulcers as we daily see among such wicked vagabondes to move the people the more to pittie."
The chemical composition of the acrid and bitter juice of the buttercups is not well known, but it is thought that the substance is similar to the anemonine of the species of Anemone. The toxic principle is volatile, and the buttercups may be rendered harmless by drying or boiling. When dried with the hay they may be eaten by stock without injury. When fresh they are acrid and burning, causing intense irritation of the mucous membrane and inflammation of the intestinal tract. Some of the species, as for instance R. repens L., are hardly if at all injurious even in a green state, although one case of fatal poisoning to sheep has been recorded of this species.
It is evident that under certain circumstances all animals are liable to suffer injury from the toxic principles of the buttercups, but they are considered especially dangerous to cows. It is stated that in man a single flower of R. sceleratus may give rise to poisonous symptoms similar to those caused by Anemone and Colchicum.
Cornevin has shown that the cursed crowfoot induces gastro-enteritis, colic, diarrhoea with excretion of black, foul-smelling faeces, vomiting when possible, falling-off in milk yield in cows, nervous symptoms, reduction in pulse, and sterterous respiration, dilation of the pupils, enfeebled condition, difficult mastication, spasmodic movements of the ears, lips, etc., followed in serious cases by convulsions, sinking of the eye in its socket, and death in six to twelve hours after first convulsion.
The symptoms of poisoning in the horse, as given by Lander, are practically the same as the above. Pott records haematuria and reddish or bitter milk in cows.
Lander also reports an instance of sheep falling down suddenly when eating R. repens, their eyes rolling. They died in a short time, with their heads inclined over the left flank.
Remedy and Means of Control: The ordinary emetics and stimulants should be given, and professional advice obtained. The weed should be cut or pulled when in its first bloom to prevent the ripening of seeds.