As angiosperms became one of the megadiverse groups of macroscopic eukaryotes, they forged modern ecosystems and promoted the evolution of extant terrestrial biota. Unequal distribution of species among lineages suggests that diversification, the process that ultimately determines species richness, acted differentially through angiosperm evolution.
Fouqueriaceae, the family of ocotillo and bojum tree, is a monogeneric clade with 11 species. Its siter group, the plox family, Polemoniaceae, has a diversity of 400 species. In this paper, we investigate the processes that have determined the species diversity of Fouquieriaceae.