The systemics of this genus are not standardized. For example, Flora of North America describes two species in the genus (in North America), H. discolor and H. microphyllus. In turn, H. discolor is divided into two varieties, var. discolor and var. dumosus. According to Flora of North America there are five species in the genus. They divide Holodiscus into two species complexes, H. discolor which includes H. discolor and H. microphyllus is found in the northern part of the species range. The others are found southward through Central America and northern South America.