Cuscuta jepsonii (Convolvulaceae): An invasive weed or an extinct endemic?

Despite their ecological significance, parasitic plants face more conservation challenges than do autotrophic plants. This is especially true for the groups that include weedy or invasive species such as Cuscuta. While approximately half of the Cuscuta (dodders) species may require conservation measures, the genus as a whole is sometimes posted on governmental lists of noxious or quarantine weeds. Our study challenges this stereotype and uses the case of C. jepsonii (Jepson's dodder) to illustrate the precarious biodiversity and conservation status faced by many dodder species. Until now, Jepson's dodder has been known only from its type collection. Consequently, its phylogenetic affinities, morphological variation, and ecology have remained unknown, and the species is currently ambiguously considered either synonymous to the invasive North American weed C. indecora or to an extinct endemic from California. Using molecular data from newly found collections, we infer that C. jepsonii belongs to C. californica species complex, instead of C. indecora clade. Also, we discuss the conservation of this species within the broader biological and ecological context of Cuscuta in general.