Source : Webster's Revised Unabridged Dictionary (1913)

Madwort \Mad"wort`\, n. (Bot.)
   A genus of cruciferous plants ({Alyssum}) with white or
   yellow flowers and rounded pods. {A. maritimum} is the
   commonly cultivated sweet alyssum, a fragrant white-flowered
   annual.

Source : WordNet®

madwort
     n : any garden plant of the genus Alyssum having clusters of
         small yellow or white flowers [syn: {alyssum}]