NOVEDADES TAXONÓMICAS EN EL GÉNERO POROPHYLLUM (ASTERACEAE, TAGETEAE): REHABILITACIÓN DE POROPHYLLUM MACROLEPIDIUM.

Porophyllum macrolepidium (previously included as a synonym of P. ruderale var. ruderale) is reinstated for South America, and its synonymy list is updated. Original descriptions and type material were studied, along with materials from the general collections housed in the main herbaria of Argentina. Field trips were conducted to study the species in its natural habitat. Exomorphological and anatomical differences with Porophyllum ruderale var. ruderale and Porophyllum ruderale var. macrocephalum are presented. An extended description ofP. macrolepidium is provided, along with illustrations, photographs, vernacular names, phenology, habitat, a map of its geographical distribution, and a dichotomous key to differentiate Porophyllum macrolepidium from related species. Additionally, the names P. macrolepidium, P. ruderale var. angustifolium, and P. ruderale var. intermedium have been lectotypified. [ABSTRACT FROM AUTHOR]