Crocanthemum bicknellii (Fernald) Janch.

hoary frostweed, hoary rock rose

Utility rights-of-way, rocky summits, and woodlands. Often in acidic sandy soils.

Herbaceous

Perennial

Vascular

6

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Arrington and Kubitzki (2003) proposed reviving the segregate genus Crocanthemum for New World members of Helianthemum sensu lato based on morphology, nuclear and chloroplast DNA phylogenies, and geography. Their molecular work also shows that Hudsonia is nested within Crocanthemum but they did not address this in their classification and left Crocanthemum (excluding Hudsonia) as paraphyletic. Guzmán and Vargas’s (2009) molecular work also support a split of the old and new world taxa of Helianthemum sensu lato and again show Hudsonia nested within Crocanthemum. As a result, we tentatively support the segregation of new world taxa of Helianthemum to the genus Crocanthemum but expect further nomenclatural adjustments will need to occur once the Hudsonia-Crocanthemum clade is fully resolved. The four species of Crocanthemum that occur in New York are C. bicknellii, C. canadense, C. dumosum, and C. propinquum.

Native S5 (State Rank)

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