Although only described towards the very end of the twentieth century, "N. benstonei" was probably first collected in July 1911 by Henry Nicholas Ridley on Mount Tahan in Pahang. The "Ridley 16097" series comprises three herbarium sheets: one deposited at the Singapore herbarium and two at Kew. The former consists of a climbing stem fragment with two upper pitchers and two female inflorescences. The two sheets at Kew are barcoded "K000651565" (climbing stem with immature female inflorescence but no pitchers) and "K000651564" (climbing stem with upper pitchers), and differ significantly in morphology. Ridley referred the "Ridley 16097" material to "N. singalana".