Nepenthes tenuis

Species of pitcher plant from Sumatra

Nepenthes tenuis (/n//ᵻ/'/p//ɛ//n//θ//iː//z// /'/t//ɛ//nj//u//ɪ//s/; ) is a tropical pitcher plant endemic to the Indonesian island of Sumatra. The species was first collected in 1957, from a remote mountain in the western part of the island. It remained undescribed until 1994, and was only rediscovered in the wild in 2002. Prior to this, N. tenuis was known solely from a single photograph and dried herbarium specimen.

Nepenthes tenuis was first collected by Willem Meijer on August 24, 1957. It was discovered near Taram, West Sumatra, in a sandstone region of the river Tjampo. The plants were growing on a ridge at approximately 1000 m above sea level, making N. tenuis an intermediate species. The habitat was described as "light sub montane forest". Nepenthes tenuis was formally described as a species in 1994 by Joachim Nerz and Andreas Wistuba, based on a single specimen deposited by Meijer at the Leiden herbarium and a black and white photograph from 1957 showing the freshly collected plant. After several failed expeditions, the species was finally rediscovered in the wild in late 2002 by a team comprising Andreas Wistuba, Joachim Nerz, Michael Schach, and others.

Nepenthes tenuis is a climbing plant. The stem is slender (2–3 mm thick) and angular to rhomboid in cross section. Internodes are 5 6.5 cm long. However, this interpretation is not followed by Charles Clarke, who does not consider the three taxa to be conspecific. Nepenthes tenuis is endemic to a region of the Tjampo river east of Taram in West Sumatra. Most ridges in this area have an elevation of just below 1000 m, although several exceed this height. Terrestrial pitchers of N. tenuis often develop partially embedded in moss. The lower parts of the stem may also be covered under a layer of moss, making the plants difficult to find in the wild. In its natural habitat, the species is sympatric with N. adnata and grows in close proximity to N. albomarginata, N. ampullaria, N. eustachya, N. gracilis, N. longifolia, and N. reinwardtiana. Despite this, no natural hybrids involving N. tenuis have been recorded. He collected N. tenuis on August 24 together with the type material of N. adnata and the first known specimen of N. longifolia. b. The original Latin description reads:

Planta tenuis. Folia mediocria sessilia lamina lanceolata, nervis longitudinalibus utrinque 3, basi attenuata 2/3 caulis amplectente. Vagina 0. Ascidia rosularum et inferiora ignota. Ascidia superiora parva, infundibuliformia, costis 2 elevatis; peristimio operculum versus accuminato in collum breve elevato, 6 mm lato, costis 1/8 mm distantibus; operculo anguste elliptico, facie inferiore piano. Inflorescentia ignota. c. The holotype of N. tenuis is Meijer 6949 H. L. B. No. 958.86.006 (L).