Viola unica (Violaceae L.), a very rare, high elevation, single site new species endemic to the northern semi-desert Altiplano of Chile

While examining the Viola collection at the herbarium (SGO) of the Museo Nacional de Historia Natural (MNHN), Santiago, we encountered a folder with a single unidentified specimen consisting of a solitary rosette. It had been found in northern Chile near the border with Bolivia, where considerable mining activity takes place. The plant appeared to differ from all others related to it as known to ourselves, and on investigation it did indeed prove to be undescribed. It is presented herein, together with a detailed analysis and preliminary partial revision of related taxa, including a key.