About 30 species of perennials from the temperate regions of both hemispheres. They are clump forming, sometimes with more or less creeping rhizomes, the mainly basal leaves oblong to orbicular with a cordate base; in some species the basal lobes are long and narrow. Mostly cup-shaped, each flower composed of five or more tepals (petal-like sepals) and a central boss of stamens.
Essentially a genus of bog, waterside or wet ground plants; not all are alpines in the true sense but they look well beside a rock garden pool. C. introloba and C. obtusa are less moisture demanding and make interesting specimens for the alpine house or moist rock garden pocket. Sunny sites are best but up to half day shade is tolerated. Propagation by seed when ripe or as soon as possible, in a cold frame, or division in autumn or after flowering.