New findings in Schinus (Anacardiaceae): delimitation of Schinus polygama and description of the new species, Schinus talampaya

Abstract

Backgrounds and aims: Schinus polygama (Anacardiaceae) has historically been a taxon of intricate taxonomy. It was erroneously considered as a species widely distributed in the Southern Cone. This work intends the delimitation of S. polygama, to describe S. talampaya (sp. nov.), previously mistaken with S. polygama and S. longifolia, and to delimitate for both the geography and biogeography in Argentina.

M&M: We revised collections of national and international herbaria, as well as newly collected materials. We consulted the pertinent protologues and specialized taxonomic literature.

Results: Schinus polygama has been delimited from its closely related counterparts. We described a new species: Schinus talampaya. The new species can be distinguished by the shape and size of leaves, kind and length of the inflorescence, number of flowers per node, pedicel length, and geographic distribution. The study of the distribution confirmed that S. polygama is restricted to Mendoza province in Argentina, while S. talampaya inhabits the provinces of La Rioja and San Juan. We provide pictures, an illustration, a comparative table with morphological data, an identification key, and distribution maps. We discuss the taxonomic placement of the involved taxa among Schinus sections.

Conclusions: The evident morphological differences between S. polygama and S. talampaya allowed us to place the two species in two different sections: Duvaua and Pilifera, respectively. The new species is an important addition to sect. Pilifera from a morphological point of view, which implies the redefinition of the defining characteristics of the section, and thus the infragenerics systematics of Schinus.