Hesperocallis is a genus of flowering plants that includes a single species, Hesperocallis undulata, the desert lily, found in the desert areas of the southwest of North America. Hesperocallis has traditionally been classified in Liliaceae but until recently its relationships have been unclear. Other classifications have included it in Hemerocallidaceae or Funkiaceae. In 1972, Hamilton Traub created the family Hesperocallidaceae with Hesperocallis as the sole included genus. The APG II system includes it in the family Asparagaceae in the order Asparagales in the monocots clade but allows for the optional segregation of Hesperocallidaceae as a monophyletic family when several other families are likewise segregated. Recent molecular systematic studies have confirmed a close relationship with Agave and its inclusion in family Agavaceae has been recommended (Pires et al. 2004).