The Clethraceae are a small family of flowering plants in the order Ericales, composed of two genera, Clethra and Purdiaea, with approximately 75 species.[2] They are native to warm temperate to tropical regions of Asia and the Americas, with one species also on Madeira.[citation needed]
In the past, most botanists included only Clethra in the family, but recent research has shown Purdiaea, previously placed in the closely related family Cyrillaceae, is more closely allied to Clethra.[3]