Some floras place our frostweeds within the genus Helianthemum; however, this key relies on recent evidence that indicates that Old World species should remain in Helianthemum, while New World species should belong to the genus Crocanthemum (Arrington and Kubitzki 2003). Species of Crocanthemum produce two types of flowers—chasmogamous flowers with showy yellow petals and cleistogamous flowers that lack petals. The chasmogamous flowers also have larger sepals and larger capsules that contain more seeds than the cleistogamous ones. Reference: Daoud and Wilbur (1965).
This Genus’s Species in New England:
Visit this genus in the Dichotomous Key