Tiarella, the foamflowers, is a genus of flowering plants in the family Saxifragaceae. The generic name Tiarella means "little turban", which suggests the shape of the seed capsules. Worldwide there are seven species, one each in eastern Asia and western North America, plus five species in eastern North America. As of October 2022, the taxonomy of Tiarella in eastern North America is in flux.

Saxifragaceae is a family of herbaceous perennial flowering plants, within the core eudicot order Saxifragales. The taxonomy of the family has been greatly revised and the scope much reduced in the era of molecular phylogenetic analysis. The family is divided into ten clades, with about 640 known species in about 35 accepted genera. About half of these consist of a single species, but about 400 of the species are in the type genus Saxifraga. The family is predominantly distributed in the northern hemisphere, but also in the Andes in South America.