Hypochaeris is similar to and closely related to Leontodon, from which it is distinguished mainly by its paleate receptacles and unequal phyllaries. Plumose pappus bristles are characteristic of both Hypochaeris and Leontodon. Molecular studies indicate the South American species of Hypochaeris are a monophyletic group derived from European stock that has undergone a recent and rapid radiation in the New World (R. Samuel et al. 2003). Two South American species are found as weeds in the flora area.