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.
Co, L. & W. Suarez 2012. Nepenthaceae. Co's Digital Flora of the Philippines.
Cullen, D. & B. Quinn 2012. Exploring Mount Victoria, Central Palawan – revisiting the habitat of N. attenboroughii. Part 1: Mt Victoria – Peak 1 & 2. Victorian Carnivorous Plant Society Journal105: 6–13.
Macfarlane, J.M. 1927. The Philippine species of Nepenthes. The Philippine Journal of Science33(2): 127–140.