broom, common name for plants of two closely related and similar Old World genera, Cytisus and Genista, of the family Leguminosae (pulse family). They are mostly twiggy leguminous shrubs with abundant yellow or white (in Cytisus, purple also) pealike blossoms. The common, or Scotch, broom ( Cytisus scoparius ) is naturalized in parts of North America; the tops have been much used as a diuretic. The Canary broom, or so-called genista of florists, is Cytisus canariensis, a yellow-flowered evergreen shrub. Species of the genus Genista include Genista tinctoria, called also dyer's-greenweed, which yields yellow-to-green dyes. Other plants are also called broom. Broom is classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Leguminosae.