Terrestrial climber to several metres tall. Leaves coriaceous, petiolate; Inflorescence to 28 cm long; Fruit with valves 44-56 by 3.5 mm. Seeds fusiform, 26 by 0.75 mm.
3. placed N. sumatrana with the remarkably similar N. treubiana of New Guinea. Nepenthes sumatrana differs by lacking teeth on the inner edge of the peristome, by lacking hairs on the leaf margins, by having ‘simple’ (i.e. with one long branch), not stellate hairs and in having larger lid nectar glands (0.2-0.7 mm diam. vs. 0.2-0.4 mm diam.). 4. Although we have seen no authentic material of Tamin & M. Hotta’s N. rafflesiana var. longicirrhosa n.n. or N. spinosa n.n., they appear to belong with N. sumatrana. 2. Although we treat N. longifolia as a synonym, it is representative of other specimens from inland Sumatra, at higher altitudes (c. 1000 m) that show differences from the plants at sea level on the coast. The inland plants have more slender pitchers which are ellipsoid in the lower half and cylindrical in the upper (not infundibuliform), with an elliptic (not a suborbicular) lid. However, intermediates are reported. More specimens are needed before N. longifolia can be fully resolved. 1 Nepenthes sumatrana appears restricted to the western half of Sumatra from Sibolga in the north to Padang in the south. The only Sumatran species with which it could be confused is N. rafflesiana. They can occur together (Clarke, pers. comm.). Both are robust lowland species with petiolate leaves and large narrowly, infundibuliform pitchers which have the front of the mouth raised. However, N. rafflesiana has terete stems, distinctively white, arachnoid indumentum, pitchers with the peristome prominently toothed on the inner edge and nectar glands absent from the central part of the lower surface of the lid. The stems of N. sumatrana when winged-ridged (they are sometimes terete) are virtually identical to those of N. burbidgeae of Borneo, which otherwise differs markedly.