[6] Nepenthes muluensis was first collected by botanist Mitsuru Hotta on March 18, 1964, on Mardi between the third and fourth camps on the western ridge of Mount Mulu, Sarawak.

At this time the genus was experiencing a revival in global interest, thanks largely to the work of Shigeo Kurata.

This misidentification was published in 1965 in the proceedings of the UNESCO Humid Tropics Symposium, which was held in Kuching two years earlier.

The peristome, which is the ring of tissue surrounding the entrance to the plant's digestive tube, is approximately cylindrical and up to 5 mm wide.

[13] Nepenthes muluensis has not been recorded from the nearby summit of Mount Benarat, although this is a limestone peak and mostly lies outside the known altitudinal distribution of the species,[6] which is 1700[5] to 2400 m above sea level.

[17] Nepenthes muluensis is most abundant in summit heath forest, where it forms dense stands with hundreds of white-speckled pitchers suspended over the sympatric shrubs.

This population produces darker pitchers than the one from Mount Mulu, possibly due to greater exposure to ultraviolet light at higher altitudes.

[1] This differs from prior assessments made by the World Conservation Monitoring Centre: in 2000 as Vulnerable[19] and in 1995 as Endangered.

[20] In 1997, Charles Clarke informally classified the species as Endangered based on the IUCN criteria, noting that it is Conservation Dependent if populations in protected areas are taken into account.

The climbing stem, growth habit and leaves are also similar, although N. muluensis usually has a narrower lamina.

However, the upper pitchers of N. muluensis are distinctive; they usually have a white lid, a round mouth, and their wings are either greatly reduced or absent altogether.

[24] The authors distinguished the taxon from N. muluensis on the basis of its branched spur and the presence of fringe hairs on the top of the lid.

[6] Although this natural hybrid is likely to exist, it is possible that N. × sarawakiensis was described based on specimens of N. muluensis with lower pitchers.

Eight spots containing phenolic acids, flavonols, flavones, leucoanthocyanins and 'unknown flavonoids' 1 and 3 were identified from chromatographic profiles.

Chromatographic patterns of the N. × sarawakiensis samples studied showed complementation of its putative parental species.

This agrees with the findings of previous authors[26][27] and suggests that the absence of a widely distributed compound like myricetin among the Nepenthes examined might provide additional diagnostic information for these taxa.