cm in width. A reduced basal crest may be present on the underside of the lid or it may be absent entirely. Other parts are similar to those found in terrestrial traps. Upper pitchers are typically yellow throughout, but some specimens may have a completely red or red-striped peristome and mature traps may be orange or reddish on the upper surface of the lid. Nepenthes flava has a racemose inflorescence up to 15 cm long. Male inflorescences are more floriferous, bearing 15–40 flowers, compared to 15–25 in females. The peduncle measures up to 4 cm in males and up to 8 cm in females. Flowers are borne solitarily on pedicels that reach 6 mm in males and 11 mm in females. A basal bract is often present (≤4 mm long). The nectariferous tepals are ovate and measure up to 3 mm in length by 1 mm in width. The androphore is around 3 mm long and terminates in an anther head measuring 1–1.5 mm in diameter. The ovary is 3–4 mm long. The morphology of the fruits and seeds has not been documented. The inflorescence is yellowish throughout. All mature vegetative parts are glabrous, but a caducous indumentum is present on some developing structures. Young parts of the stem bear a sparse covering of reddish-brown, basally branched hairs (0.2–0.5 mm long). A dense indumentum of reddish-brown hairs (0.5–1 mm long) is present on developing pitchers and tendril ends. The inflorescence bears branched, yellowish-brown hairs measuring 0.5–1 mm in length. Tepals have a dense covering of curved, reddish-brown hairs (around 0.2 mm long) along their margins. Ovaries also have a dense covering of reddish-brown hairs, but these are longer, measuring 0.5–1 mm. Ecology Nepenthes flava is only known from a single mountain in the Barisan Mountains of North Sumatra, Indonesia. In the interests of conservation, the exact locality has not been disclosed. The species has an altitudinal distribution of 1800–2200 m above sea level. The typical habitat of N. flava is upper montane mossy forest dominated by Rhododendron and Leptospermum plants. It often grows terrestrially in more open areas of forest, where the vegetation rarely exceeds 4–5 m in height. The species is naturally sympatric with N. mikei, N. ovata, N. rhombicaulis, and N. spectabilis. Natural hybrids with N. ovata and N. rhombicaulis have been recorded. The only known locality of N. flava does not lie within the boundaries of a