Mimulus, a genus of plants of the natural order Scrophulariaceæ, having a prismatic 5-toothed calyx, a somewhat bell-shaped corolla, of which the upper lip is bifid and the lower lip trifid, two long and two short stamens, and a stigma of two lamellæ, which close together upon irritation. The species are mostly herbaceous plants, natives of America. Some of them are very frequent in flower-gardens, and many fine varieties have resulted from cultivation. They sometimes receive the name of Monkey-flower. One species, M. luteus, a native of Peru and Chili, and there used as a potherb, has become naturalised in many parts of Britain. The little yellow-flowered Musk Plant, now so common in gardens and on window-sills in Britain, is M. moschatus, a native of Oregon and other north-western parts of America.