Aristolochia stevechurchillii, a new pseudostipule-bearing Aristolochiaceae (Piperales) from Bolivia, with a key to identify the species of the ´Pseudostipulosae´ group in the country

Abstract

A new pseudostipule-bearing species of Aristolochia, A. stevechurchillii, is here described and illustrated, along with a key to identify all the species of the informal ´Pseudostipulosae´ group naturally occurring in Bolivia. The new species differs from its closely related species by the formation of two serial flowers per axil, the base of the utricle with six retrorse digitiform processes, and the perianth limb narrowly ovate, with acute apex. Along with A. andina and A. lozaniana, A. stevechurchillii is the third species of the genus endemic from mid-elevation (1600-2500 m) Tucumano-Bolivian forests of the departments of Cochabamba, Chuquisaca and Tarija (Bolivia). The new species is morphologically similar to A. melanoglossa, from northern Argentina, which provides additional evidence to floristic affinities previously proposed between the Tucumano-Bolivian forests and the Chaco vegetation.