 Phylogenetic analyses based on DNA from the nuclear genome as well as mitochondrial and chloroplast DNA suggest that "H. palmeri" is closely related to the genera "Forestiera" and "Priogymnanthus" in tribe Oleeae, and perhaps the sister lineage of "Forestiera".A molecular clock analysis estimated its divergence from its closest relatives in the Early Miocene, likely pre-dating the age of Guadalupe Island.This suggests that "H. palmeri" is a paleoendemic that was once more widespread and then retreated to Guadalupe Island following environmental change.