GEUM, in botany, a genus of hardy perennial herbs (family Rosaceae), containing about 4o species, widely distributed in tem perate and arctic regions. The erect flowering shoots spring from a cluster of radical leaves, which are deeply cut or lobed, the largest division being at the top of the leaf. The flowers are borne singly on long stalks at the end of the stern or its branches. They are white, yellow or red in colour, and shallowy cup-shaped. The fruit consists of a number of dry achenes, each bearing a hook formed from the persistent lower portion of the style, and ad mirably adapted for ensuring distribution. Two species occur in Great Britain; avens, G. urbanum, is a common hedge-bank plant with small yellow flowers; G. rivale (water avens) is a rarer plant, found by streams, and has larger yellow flowers an inch or more across. About 15 species, including G. rivale, are natives of North America. Several species are easy to cultivate and well adapted for borders or the rock-garden. They are propa gated by seeds or by division.