5.2 cm in width. The pitcher mouth is horizontal and orbicular. As in lower pitchers, the inner surface of the pitchers is wholly glandular. Wings are reduced to ribs that run down the front of the pitcher. In aerial pitchers, the flattened peristome is up 6 mm wide and bears more prominent teeth (≤1 mm long). The spur is usually simple and grows to 3.5 mm in length. Compared to lower pitchers, the lid in upper pitchers is similar in shape but longer, reaching 4.8 cm in length and 0.9 cm in width. It is held over the pitcher mouth at an angle of approximately 45 degrees. Nepenthes jamban has a racemose inflorescence. In male plants, the inflorescence may be up to 18 cm long. The female inflorescence has not been described. The rachis is up to 11.5 cm long, while the peduncle is up to 6.5 cm long. Pedicels are up to 1.4 cm long and bear a single flower. Sepals are elliptical and around 3.5 mm long. Mature fruits are up to 3 cm long and 6 mm wide. Seeds are filiform and around 2 cm long. Most parts of the plant are glabrous. Developing pitchers, tendrils, and inflorescences are densely covered with short brownish-grey hairs. The stem is characteristically purplish red. The leaves and inflorescence are light green to pale green. Lower pitchers range in colour from yellowish orange to bright red throughout. Upper pitchers are generally bright yellow with a yellow to orange peristome, and may be occasionally speckled on their inner surfaces. Ecology Nepenthes jamban is endemic to the Barisan Mountains that line the western side of Sumatra. It is known only from the type locality, south of Padang Sidempuan in North Sumatra. The species has an altitudinal distribution of 1800–2100 m above sea level. Nepenthes jamban grows in upper montane mossy forest amongst summit scrub vegetation. Unlike the closely related N. jacquelineae, it only occurs terrestrially. In the wild, N. jamban occurs sympatrically with N. bongso, N. dubia, N. gymnamphora, and N. lingulata. A natural hybrid with N. lingulata has been recorded. Carnivory The upper pitchers of N. jamban have been noted for trapping many large prey items, such as wasps and crickets, and relatively few small animals. The traps of this species also support large populations of pitcher infauna, particularly mosquito larvae. Nepenthes jamban produces thick, mucilaginous pitcher liquid similar to that found