Stevia mandonii (Asteraceae, Eupatorieae): First record for the Argentine flora and lectotypification

Abstract

Stevia Cav. (Asteraceae, Eupatorieae) includes ca. 235 species distributed from United States of America to Chile and Argentina in South America. During the taxonomic revision of the Argentinian species several specimens belonging to Stevia mandonii Sch. Bip. were found in the province of Jujuy, where it had not been previously cited. In this framework, the goals of the present article are 1) to report the species in Argentina for the first time, 2) to differentiate it among morphologically close species, and 3) to perform a taxonomical analysis based on herbarium specimens, populations in the field, bibliography and type material. Morphology was analyzed by means of optical microscopy and scanning electron microscopy techniques. Stevia mandonii is readily distinguished by its small size of 10-20 cm, rounded leaves and pappus formed by 9-17 bristles with presence of heterocarpy. A detailed morphological description, an illustration, a geographic distribution map, and a key to species of Stevia that occur in Jujuy are provided. The designation of a lectotype for the name Stevia mandonii is properly discussed.