Morphological, molecular, and biogeographic evidence for specific recognition of Euthamia hirtipes and Euthamia scabra (Asteraceae, Astereae)

The number and identity of species in the North American genus Euthamia (Asteraceae, Astereae) have varied considerably among taxonomic treatments. Euthamia graminifolia (L.) Nutt. is often treated to broadly include plants from the northern and eastern United States and Canada, including the Atlantic and Gulf Coasts. Broad-leaved, largely glabrous plants from New Jersey to the Florida Panhandle have been inconsistently treated as E. graminifolia, E. graminifolia var. hirtipes (Fernald) C.E.S. Taylor & R.J. Taylor E. hirtipes (Fernald) Sieren , or a hybrid between E graminifolia and E. caroliniana (L.) Greene ex Porter & Britton . Similarly, plants from the Florida Panhandle to eastern Louisiana have been incorporated into either E. graminifolia or E. graminifolia var. hirtipes, with only Greene in 1902 recognizing southern plants as a distinct species, E. scabra Greene . To determine the identity and proper rank of these entities,
morphological and p...