Taxonomic revision of the peculiar genus (Loasaceae) with a new species from Argentina and Bolivia demonstrating an atypical trans-Andean disjunction.

Loasaceae subfam. Loasoideae are a nearly exclusively American plant group with a center of diversity in Peru. Numerous new taxa have been described over the past decades; one of the most striking discoveries was that of the narrowly endemic with the single species in Peru, Dpto. Cajamarca in 1997. Surprisingly, field studies in the past years have resulted in the discovery of material clearly belonging to the same genus in both Bolivia and northern Argentina, approximately 1500 km SE of the next known population of in Contumazá, Peru. A closer examination shows that Argentinian and Bolivian material belongs to a single species, clearly different from . We here describe and the entire genus is revised. Both species are illustrated, all aspects of their biology and ecology are portrayed and their threat status is discussed.