The ponderosa lemon (Citrus × pyriformis) (also called Skierniewice lemonKonarska, A., and E. Weryszko-Chmielewska. "Micromorphology, anatomy and ultrastructure of nectaries in two types of flowers of Citrus limon cv.‘Ponderosa’." Acta Scientiarum Polonorum. Hortorum Cultus 15.6 (2016).) is a citrus hybrid of a pomelo and a citron. It is not the same as the 'Yuma Ponderosa' lemon-pomelo hybrid used as citrus rootstock.
