The genus Pinguicula contains the 83 species of butterworts, belonging to the bladderwort family (Lentibulariaceae). It has a natural distribution across most of the Northern Hemisphere, though over half of the species are concentrated in Mexico and Central America. Siegfried Jost Casper systematically divided them into three subgenera with 15 sections. Subsequent phylogenetic research showed that many of these groupings are polyphyletic, but they are used below.