Ultrahighland species, which I characterize as growing at a minimum altitude of 2000 m
or more, are the following: NN. murudensis, singalana, macrophylla, aristolochioides,
villosa, diatas, and inermis. I would also include the "Doorman's Top" variety of
N. lamii in this group, as it grows higher than any other Nepenthes.
Other species which grow at a minimum elevation of 1000 m or above, I would merely
consider as highland species, or in the case of those growing from 1000 to 1300 m,
intermediates.