very few immature plants were visible". Related species Nepenthes spectabilis is thought to be most closely related to N. lavicola. It can be distinguished from that species on the basis of its smaller floral bracts, longer fruits, and very long unbranched spur. In addition, the species differ in the shape of their lower pitchers. Those of N. lavicola are urceolate to globose, while those of N. spectabilis are ovoid in the lower part and cylindrical above. Furthermore, the pitchers of N. lavicola are generally dark brown or purple throughout, compared to the light green and dark brown speckled traps of N. spectabilis. In Nepenthes of Sumatra and Peninsular Malaysia, Charles Clarke mentions an undescribed taxon from Aceh that is intermediate in appearance between N. lavicola and N. spectabilis. It is unlikely to be of hybridogenic origin as it is not sympatric with any other Nepenthes species. Nepenthes rigidifolia also bears a superficial resemblance to N. spectabilis, particularly in the colouration of its pitchers. Apart from its markedly different upper pitchers, N. spectabilis differs from the former in having thin leaves, an unbranched spur, and an apical tendril insertion. In his 1928 monograph, B. H. Danser placed N. spectabilis in the Nobiles clade. He wrote: The third group, that of the Nobiles, comprises the species that form a transition between the Vulgatae and the Montanae on one hand and the Regiae on the other. N. spectabilis, from Sumatra, reminds one of N. sanguinea in many respects but shows a resemblance with the Regiae by the yellowish colour of herbarium specimens and by the red-brown indumentum. Clarke suggests that N. spectabilis "would perhaps have been better placed in the Montanae, which includes several species that appear to be closely related, such as N. gymnamphora and N. pectinata". In 2001, Clarke published a cladistic analysis of the Nepenthes species of Sumatra and Peninsular Malaysia based on 70 morphological characteristics of each taxon. The resultant cladogram placed N. spectabilis in a small clade with N. gymnamphora. However, since the study was limited in its geographical scope, this placement may not accurately reflect the relationship between N. spectabilis and its closest relatives. Natural hybrids Nepenthes spectabilis occurs sympatrically with many other Nepenthes species and a number of natural hybrids have been recorded. N. ovata × N. spectabilis Nepenthes ovata × N. spectabilis is known to occur along the summit trail of Mount Pangulubao. This hybrid