a European bellflower (Campanula rapunculus) with thick, fleshy, white roots that are used with the leaves in salads or cooked, esp. formerly, as a vegetable
See rampion in American Heritage Dictionary 4
(rămˈpē-ən)
noun
A biennial Eurasian plant (Campanula rapunculus) having rosette leaves with winged stalks, panicles of lilac-colored flowers, and an edible root used in salads.
Any of various similar plants of the genus Phyteuma.