Source : Webster's Revised Unabridged Dictionary (1913)

Water agrimony \Wa"ter ag"ri*mo*ny\ (Bot.)
   A kind of bur marigold ({Bidens tripartita}) found in wet
   places in Europe.

Source : WordNet®

Bidens tripartita
     n : of temperate Eurasia [syn: {European beggar-ticks}, {trifid
         beggar-ticks}, {trifid bur marigold}]