Alyssum
Alyssum, a genus of herbs. Members of this genus are commonly called madworts. There are about 160 species, all native to Europe and Asia. Sweet alyssum is a related plant. (See Sweet Alyssum.)
Alyssums seldom exceed 12 inches (30 cm) in height. The flowers are usually white or yellow, and grow in dense clusters at the end of the stems. Most alyssums grow easily in ordinary garden soil and require very little cultivation. The most popular species is the golden tuft, or gold dust.
Golden tuft is Alyssum saxatile. Alyssums belong to the mustard family, Cruciferae.