Abstract
The new species Dioscorea megaphylla (Dioscoreaceae) is described and illustrated with photographs. It is known onlyfrom the type locality, along the coastal foothills of the Sierra de Coalcomán in the municipality of Aquila, Michoacán, Mexico, where it grows in rocky canyons and hillsides with tropical subdeciduous forest at elevations of 550–600 m. As the specifi c epithet suggest, this species is distinctive due to the size of its leaves, and these are the largest within the genus Dioscorea and measure as much as 60 cm long and 65 cm wide. Unlike most members of the genus, fl owering occurs at the end of the dry season on newly produced stems before the leaves mature. Dioscorea megaphylla belongs to sect. Macrogynodium and is closely related to D. nelsonii and D. carpomaculata.