Ranunculus bulbosus, commonly known as St Anthony's turnip or bulbous buttercup, is a perennial weed of the Buttercup Family. It has attractive yellow flowers, and deeply divided, three-lobed long-petioled basal leaves. Bulbous buttercup is known to form tufts.
The stems are 20-60 cm tall, erect, branching, and slightly hairy flowering. There are alternate and sessile leaves on the stem. The flower forms at the apex of the stems, and is shiny and yellow with 5-7 petals. The flowers are 1.5-3 cm wide. The plant blooms from April to July.
Bulbous buttercup gets its name from its distinctive perennating organ, a bulb-like swollen underground stem or corm, which is situated just below the soil surface. After the plant dies in heat of summer, the corm survives underground through the winter. Although the presence of a corm distinguishes Ranunculus bulbosus from some other species of buttercup such as Ranunculus acris, the species also has distinctive reflexed sepals. Other common names for bulbous buttercup include: St. Anthony's turnip, blister flower, and bulbous crowfoot.
Buttercups contain poisons 1% glycoside ranunculin in corm, and are avoided by livestock. Note however that the poisons of buttercup are lost upon drying, so any hay containing bulbous buttercup is safe for animal consumption. Protoanemonin is an irritating antibiotic, formed from enzymatic breakdown of ranunculin.
In spite of its toxic nature, this plant is listed as an herbal remedy. Used in Homeopathy for subepidermal blistering of the skin especially in summer.