A new southern hemisphere species of Potentilla (Rosaceae)

Potentilla tucumanensis A. Castagnaro & M. Arias, sp. nov., from Tucuman, A rgentina, is described and illustrated. Potentilla tucumanensis was origina lly determined as P. norvegica. The latter and P. anserina were the only tw o species of this large genus primarily of the Northern Hemisphere cited fr om Argentina. Potentilla tucumanensis is distinguished from P. norvegica by morphological-reproductive (flowers and achenes), anatomical (stomata), an d genetic (chromosome number) characters.