1) Alyssum 2) Crucifer 3) Cruciferous plant 4) Plant thought to cure rabies 1) Alyssum 
• (n.) 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.
Mad'wort` noun (Botany) 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. 
noun any garden plant of the genus Alyssum having clusters of small yellow or white flowers