Nepenthes philippinensis produces the most concurrent inflorescences of any species in the genus; up to 190 have been recorded on a single plant.[12]
Nepenthes philippinensis has no known natural hybrids.[12] No forms or varieties have been formally described, although a multitude of taxa resembling N. philippinensis are found across the isolated peaks of Palawan.[9][13]
^Cheek, M. & M. Jebb 2013. Typification and redelimitation of Nepenthes alata with notes on the N. alata group, and N. negros sp. nov. from the Philippines. Nordic Journal of Botany31(5): 616–622. doi:10.1111/j.1756-1051.2012.00099.x
^ abMcPherson, S.R. 2011. Observations of Nepenthes philippinensis and related taxa. In: New Nepenthes: Volume One. Redfern Natural History Productions, Poole. pp. 382–395.