Why has this species not been recollected since 1911 in spite of several botanical expeditions to G. Tahan since then? The answer is quite simple, Ridley's specimen (16097) actually belongs to "N. gracillima". Although "N. alata" Blanco is superficially similar to "N. gracillima" in its narrow leaf blade which has an attenuate base, the pitchers of these two species are distinct. Those of "N. alata" are broader (about 4 cm wide) and are distinctly bulbous towards the base compared with the very slender, non-bulbous pitchers of "N. gracillima" that are 1.5 to 3 cm wide. Nor does the G. Tahan specimen have truly petiolate leaves - its leaf base is narrow and has rolled up during drying. Ridley's specimen from G. Tahan determined by Danser as "N. alata" bears pitchers typical of "N. gracillima" and examination of the Tahan population in the field leaves no doubt that it belongs to this species.