Nepenthes copelandii belongs to the informal "N. alata group", which also includes N. alata, N. ceciliae, N. extincta, N. graciliflora, N. hamiguitanensis, N. kitanglad, N. kurata, N. leyte, N. mindanaoensis, N. negros, N. ramos, N. saranganiensis, and N. ultra.Cheek, M. & M. Jebb 2013. Recircumscription of the Nepenthes alata group (Caryophyllales: Nepenthaceae), in the Philippines, with four new species. European Journal of Taxonomy 69: 1–23. Cheek, M. & M. Jebb 2013. Nepenthes ramos (Nepenthaceae), a new species from Mindanao, Philippines. Willdenowia 43(1): 107–111. Cheek, M. & M. Jebb 2013. Nepenthes ultra (Nepenthaceae), a new species from Luzon, Philippines. Blumea, published online on October 24, 2013. These species are united by a number of morphological characters, including winged petioles, lids with basal ridges on the lower surface (often elaborated into appendages), and upper pitchers that are usually broadest near the base.
