The Collaborative International Dictionary of English v.0.48:

Water celery \Wa"ter cel"er*y\ (Bot.)
   A very acrid herb (Ranunculus sceleratus) growing in
   ditches and wet places; -- called also cursed crowfoot.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cursed crowfoot
    n 1: annual herb growing in marshy places [syn: cursed
         crowfoot, celery-leaved buttercup, Ranunculus
         sceleratus]