However, in his 2001 book, "Nepenthes of Sumatra and Peninsular Malaysia", Charles Clarke disagreed with Kiew's identification of "Ridley 16097" as "N. gracillima". He noted that the inflorescences of both "N. gracillima" and the closely related "N. ramispina" are very short, rarely exceeding 10 and 20 cm, respectively. Both female inflorescences of "Ridley 16097" have a long peduncle and rachis, each exceeding 20 cm in length. In addition, the flowers of these species are almost always borne on pedicels, unlike those of "Ridley 16097", which mostly have two-flowered partial peduncles. Furthermore, the shape of the lamina is unlike that of "N. gracillima" or "N. ramispina"; despite being narrow and lanceolate, it is proportionately considerably longer and has a much narrower, almost sub- base. Kiew partly attributed the narrower leaf bases of "Ridley 16097" to a preservation artefact, but Clarke stated that this explanation could not fully account for the differences. He also noted that the specimen exhibits a leaf attachment. Taking all of these morphological features into account, Clarke felt that "Ridley 16097" most likely represented a specimen of "N. benstonei". At the time, he believed that Kiew had grouped both "N. benstonei" and "N. ramispina" with "N. gracillima". But in a 2012 revision of the "Nepenthes" of Mount Tahan, which included a reappraisal of the taxonomically confused "N. alba" and "N. gracillima", Clarke and Ch'ien Lee concluded that Kiew's concept of "N. gracillima" had encompassed "N. alba", "N. benstonei", and "N. gracillima". Clarke and Lee also showed that "Ridley 16097" represents a mixed collection and that only two of the three sheets belong to "N. benstonei"; the Kew specimen barcoded "K000651564" is representative of "N. alba".