Nepenthes flava is a tropical pitcher plant endemic to northern Sumatra, where it grows in montane forest at 1800–2200 m above sea level. The specific epithet flava is derived from the Latin word for "yellow" and refers to the typical colouration of the plant's upper pitchers and other vegetative parts. Botanical history Nepenthes flava entered cultivation several years prior to being described and was known from at least 2004 under the placeholder name "Nepenthes spec. nov. Sumatra". The species was formally described by Andreas Wistuba, Joachim Nerz and Andreas Fleischmann in an issue of Blumea published on July 4, 2007. The description was based on cultivated plant material; Wistuba cult. Wistuba 100201 was designated as the holotype. This specimen was collected at an altitude of 1800 m and is deposited at the National Herbarium of the Netherlands (L) in Leiden, together with an isotype. The describing authors explained their choice of the specific epithet flava as follows: The specific epithet ‘flava’ refers to the bright yellow colour of the upper pitchers and most of the lower pitchers. Climbing plants especially give the impression of a mainly yellow plant. A detailed and slightly modified description of N. flava appeared in Stewart McPherson's 2009 monograph, Pitcher Plants of the Old World. Whereas the type description mentions a basal crest on the underside of the lid, McPherson writes that no appendages are present in either lower or upper pitchers. Description Nepenthes flava is a climbing plant growing to a height of 6 m. It only remains in the rosette stage for a short time before transitioning into a scrambling vine. The stem, which may be branched, is around 3 mm in diameter and has roughly cylindrical internodes measuring up to 14 cm in length. The stem ranges in colour from green to dark red. The lamina (leaf blade) is linear, oblong, or narrowly obovate, and measures up to 9 cm in length by 2.5 cm in width. Its apex is usually acute, but may also be obtuse. The base of the lamina is attenuate and clasps the stem for around half to three-quarters of its circumference. Three prominent longitudinal veins are present on either side of the midrib. Indistinct reticulate veins are also present. The lamina is yellowish-green in colour and the midrib may be reddish. Tendrils reach 24 cm in length and may be green to red. Rosette and lower pitchers are