Abstract
Two unispecific genera, Eccremis and Pasithea , are the only representatives of Hemerocallidaceae (Asparagales) native to the Western Hemisphere. The affinities of the former genus have been recently questioned. Phylogenetic analyses of DNA sequence data (plastid atpB, ndhF, rbcL, trnL-F ) spanning the Asparagales recover a monophyletic Hemerocallidaceae and strongly support the inclusion of Eccremis within that family. Eccremis is sister to Dianella and not closely associated with Pasithea , which indicates two introductions of Hemerocallidaceae to the New World. A taxonomic synopsis of Eccremis and Pasithea is presented and morphological character evolution and biogeography are discussed.