| Noun | 1. | genus Sisymbrium - genus of Old World annual or biennial or perennial herbs with racemose flowers; many are considered to be weeds dilleniid dicot genus - genus of more or less advanced dicotyledonous trees and shrubs and herbs Brassicaceae, Cruciferae, family Brassicaceae, family Cruciferae, mustard family - a large family of plants with four-petaled flowers; includes mustards, cabbages, broccoli, turnips, cresses, and their many relatives hedge mustard, Sisymbrium officinale - stiffly branching Old World annual with pale yellow flowers; widely naturalized in North America; formerly used medicinally |