Plant of the week: Extremely poisonous plant induces blisters

Name: Buttercup (Ranunculus bulbosus)

Otherwise known as: Frogfoot, St Anthony’s Turnip

Habitat: A perennial member of the Ranunculaceae family growing up to 20cm in meadow and woodland and native to Europe. The plant has delicate stems emanating from a bulbous root and the furrowed stems sport long, narrow, segmented leaves which support the familiar bright yellow flower. The fresh plant is highly toxic to grazing animals and has proven fatal in humans.

What does it do: There are over 400 varieties of this plant and they all contain protoanemonin glycosides that have been used since ancient times to remove warts and raise blisters. Dioscorides suggested the juice of the plant be applied to rheumatic joints to induce blisters that would draw the pain from the afflicted part. Gerrard recommended the application of a poultice made from the bulb-like root to be positioned between the ribs to cure shingles (Herpes zoster), it apparently worked by raising competing blisters. Culpeper claimed that there was no better treatment for sciatica than the application of the juice from the stems to the base of the spine.

In medieval Europe, street beggars would rub it on their faces and into wounds to sustain their scabrous appearance. There is an interesting piece of American folk lore attached to the plant: in the Nez Pierce tribe the plant is known as ‘coyote’s eyes’ because it was claimed that the coyote when off on a frolic took out his eyes and threw them in the air where they were seized on by an eagle, and in desperation, the coyote grasped the turnip and replaced his eyes with the flowers.

All members of this family are poisonous, and instances where they have been consumed, either in times of famine, or inadvertently, have caused excessive blistering of the mucous membrane, bloody diarrhea, dramatic salivation, severe dermatitis and death. However, drying degrades the toxins, and some central European countries have eaten the corms in times of hardship, when they were considered quite palatable.