The genus Cuscuta is composed of a large number of morphologically similar stem parasitic vines. They produce minute, scale-like leaves with flower structure that is often only discernable microscopically. The morphological reduction of Cuscuta has historically rendered them a taxonomically difficult group, although most authorities have agreed they are allied to Convolvulaceae (Morning Glories). Even molecular systematic approaches have proven confounding, as the chloroplast and nuclear genes most often used in broad phylogenies have been shown to evolve at accelerated rates in parasitic plants, sometimes leading to incorrect phylogenetic inferences. Mitochondrial gene and intron sequences have revealed a sister relationship of Cuscuta to members of Convolvulaceae rather than suggesting Cuscuta is nested within the family. A Nuclear ITS phylogeny provides insights into the relationships between the three traditionally recognized subgenera of Cuscuta along with a more detailed interspecific phylogeny. These relationships have a significant impact on the understanding of the evolution of parasitism and photosynthesis in Cuscuta.

Key words: Convolvulaceae, Cuscuta, ITS, mitochondrial DNA, parasitic plant, systematics