A single mature female plant of N. dubia × N. izumiae grows along the summit trail on Mount Talakmau. It produces infundibular upper pitchers that are yellowish-green in colouration. The pitchers are relatively small, reaching only around 10 cm in height. As in N. dubia, the stem and tendrils are purplish-red. The lamina is green with a red midrib. Nepenthes dubia × N. izumiae differs most obviously from N. dubia in having an ovate lid that is never reflexed beyond 180 degrees. This hybrid is listed as N. dubia × N. singalana in Charles Clarke's Nepenthes of Sumatra and Peninsular Malaysia, since N. izumiae is very closely related to N. singalana and was only described as a distinct species in 2003.