No end to endemism - contributions to the difficult Nasa Weigend Series Alatae (Loasaceae). A new species from Peru and the rehabilitation of “Loasa” calycina Benth

A new species of Nasa ser. Alatae (Urban & Gilg) Weigend from Northern Peru is described and illustrated. Nasa katjae sp. nov. was at first encountered by an observation on iNaturalist and subsequently collected in the humid Andean forests near Colasay in the province of Jaén (Cajamarca, Peru). Whilst comparing the new species with closely related Nasa loxensis (Kunth) Weigend, a taxon widespread in Southern Ecuador (and tentatively adjacent Peru), a reevaluation of the status of earlier synonymized Loasa calycina Benth. became necessary. Consequently, Nasa calycina comb. nov. is rehabilitated at species level and Nasa loxensis is redefined.