or branched hairs, although these are mostly caducous. Short brown hairs are present on the leaf margins. No forms or varieties of N. sumatrana have been described. Distribution and habitat Nepenthes sumatrana is endemic to the Indonesian provinces of North Sumatra and West Sumatra. It is best known from the hills around Sibolga, where it was first collected. The species has a patchy distribution and the full extent of its geographical range is uncertain. Specimens collected near Sawahlunto and named Nepenthes spinosa by Tamin and Hotta appear to be conspecific with N. sumatrana, although trips to the area in 1995 and 2001 failed to locate any plants. Nepenthes sumatrana grows terrestrially in dense, undisturbed lowland forest on sandstone substrates. Moist, shady conditions appear to be vital to the survival of the species, as it has not been recorded from areas that have been cleared due to logging or agricultural activities. These requirements might explain the fragmented nature of its distribution and suggest that N. sumatrana is more seriously threatened with extinction than previously thought. Plants are often found on very steep slopes. Seedlings of N. sumatrana have been recorded from open cliff faces, but it is uncertain whether these survive to maturity, as larger plants are only known from the forests, where their stems can use surrounding objects for support and climb into the canopy. Nepenthes sumatrana has been recorded from elevations of between 0 and 800 m above sea level. Conservation status The conservation status of N. sumatrana is listed as Critically Endangered on the 2014 IUCN Red List of Threatened Species. However, prior to the 2013 re-evaluation, N. sumatrana had not been re-evaluated since 2000 and treated N. longifolia in synonymy with N. sumatrana. Recent studies have shown that these two taxa are distinct species. In 2001, based on first hand observations of wild populations, Charles Clarke informally reclassified N. sumatrana as Critically Endangered according to the IUCN criteria. Clarke notes that N. sumatrana seems to be unable to survive in disturbed habitats. As such, rapid development around Sibolga poses a particularly serious threat to the survival of the species in the wild. In comparison, the threat of over-collection is relatively small, since many plants grow on very steep slopes which are virtually inaccessible. Taxonomic confusion concerning N. sumatrana and closely related species such as N. beccariana and N. longifolia makes the implementation of new conservation projects all