Nepenthes holdenii

Nepenthes holdenii is a tropical pitcher plant from western Cambodia, where it grows at elevations of 600–800 m above sea level. The species was originally known from only two peaks in the Cardamom Mountains, but the discovery of a new population was reported in October 2011. Seeds were collected in 2014 and the species was successfully introduced into cultivation.

Description
Leaves are coriaceous, subpetiolate, lamina linear to linear-lanceolate, 25-40 cm long, 3.5-6 cm wide, apex acute, clasping the stem by 1/2 of its circumference, decurrent on rosette and on climbing stem on 3-4 cm projecting from the stem as wings. There are three longitudinal nerves (rarely 4) on each side of the midrib in the outer third of the leaf. In the dry season, the leaves are modified into pitchers to capture and digest insects. The pitchers can reach up to 30cm long. In contrast to other closely related species, it has long tendrils and globose lower pitchers.

Habitat and Distribution
Nepenthes holdenii occurs in localities situated in the transitional zone between lowland evergreen forest and low montane evergreen forest.

Etymology
It was previously collected and diagnosed by Lecomte in the 1909 as Nepenthes thorelii, which is now considered an aggregate of Indochinese Nepenthes species. It was photographed by biologist Jeremy Holden in 2006; Mey used these photographs, in situ examination of closely related species, and the previously collected specimen to distinguish N. holdenii from N. thorelii.

Closely Related Species
These species are considered to be part of the Nepenthes thorelii aggregate.
 * N. andamana M. Catal. (2010)
 * N. bokorensis Mey (2009)
 * N. chang M. Catal. (2010)
 * N. kampotiana Lecomte (1909)
 * N. kerrii M. Catal. & T. Kruetr. (2010)
 * N. smilesii Hemsley (1897)
 * N. suratensis M. Catal. (2010)
 * N. thorelii Lecomte (1909)