Lycianthes (Dunal) Hassler is accepted as a genus more closely related to Capsicum L. and Witheringia L'Heritier, rather than to Solanum L.; the evidences are based on the structure and the inervation of the calyx. With a tropical and subtropical range, the genus is represented in the northern part of the Argentinian territory by the following 5 species: L. asarifolia (Kunth et Bouché) Bitter, L. australe (Morton) A. T. Hunz. et Barboza nov. comb., L. lycioides (L.) Hassler, L. rantonnei (Carrière) Bitter and L. saltensis Bitter. The key to facilitate the identification of these species includes androecium characters hitherto not mentioned in the literature, vgr.: heterodynamous versus homodynamous stamens, filaments with or without a basal hump in its free portion, etc. These characters, together with the remaining ones that are useful for the specific delimitation, are thoroughly discussed in the text. [ABSTRACT FROM AUTHOR]