The Collaborative International Dictionary of English v.0.48:

Rampion \Ram"pi*on\ (r[a^]m"p[i^]*[u^]n), n. [Cf. F. raiponce,
   Sp. ruiponce, reponche, L. raperonzo, NL. rapuntium, fr. L.
   rapum, rapa, a turnip, rape. Cf. Rape a plant.] (Bot.)
   A plant (Campanula Rapunculus) of the Bellflower family,
   with a tuberous esculent root; -- also called ramps.
   [1913 Webster]

   Note: The name is sometimes given to plants of the genus
         Phyteuma, herbs of the Bellflower family, and to the
         American evening primrose ([OE]nothera biennis),
         which has run wild in some parts of Europe.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Campanula rapunculus
    n 1: bellflower of Europe and Asia and North Africa having
         bluish flowers and an edible tuberous root used with the
         leaves in salad [syn: rampion, rampion bellflower,
         Campanula rapunculus]