RESUMEN
ABSTRACT Viola maculata Cav., Violaceae, grows in the underwood along the Los Andes mountain system from Neuquén to Tierra del Fuego and Islas Malvinas. It is also known as violeta amarilla or as pilundeu, and is used in popular medicine by the Mapuches as stimulant, in dermatology, and as a lavage in eye diseases. The aim of this work is to examine the morpho-anatomical traits of the leaves and petiole of V. maculata (collected at Parque Nacional Los Alerces, Patagonia, Argentina). Cross sections and scanning electron microscopy of leaves blade and petiole showed a simple organization with simple unicellular trichomes and cells containing tannins, and crystals of calcium oxalate mainly in the spongy parenchyma. As V. maculata is used in traditional medicine, the specification of the anatomical characters is relevant to describe the species.