Alfindra Primaldhi · CC BY 2.0
About
This striking species, *Nepenthes rhombicaulis*, is notable for its exceptionally long climbing stems, which can reach up to 35 meters, making it one of the longest in the genus. Its lower pitchers often develop embedded in leaf litter, suggesting an adaptation for trapping subterranean insects.
Field notes
Morphology
The plant climbs well, with internodes up to 20 cm long and 1 cm in diameter, usually rhomboid in cross section. Leaves are lanceolate-spathulate, up to 25 cm long and 4 cm wide, with an acute to sub-peltate apex. Lower pitchers are ovoid to ventricose, reaching 12 cm in height and 4 cm in width, featuring a pair of fringed wings (≤3 mm long). The peristome is sub-cylindrical to irregularly expanded and up to 5 mm wide, lined with distinct, papery teeth up to 3 mm long. The lid is ovate and may bear a small apical appendage, and a spur (≤5 mm long) is inserted near its base. Upper pitchers are ventricose in the lower parts and elongated above, becoming tubiform or slightly infundibuliform towards the mouth, with a greatly reduced peristome.
Distribution & habitat
Endemic to Sumatra, specifically known from the Mount Pangulubao complex and Mount Lubukraya, with an altitudinal range of 1,600–2,000 m above sea level. It is also recorded from Mount Bandahara in Aceh.
Ecology
The species grows terrestrially in dense, shady montane forest, often found in the understory. Lower pitchers frequently develop embedded in detritus and leaf litter, leading to the hypothesis that the plant is adapted to trapping subterranean insects. It occurs sympatrically with *N. flava*, *N. ovata*, *N. spectabilis*, and *N. tobaica*.
History & etymology
The specific epithet *rhombicaulis* is derived from the Latin words *rhombicus* (rhomboid) and *caulis* (stem), referring to the cross-sectional shape of the stem internodes. It was first collected by Shigeo Kurata on March 29, 1972, on Mount Pangulubao. Kurata formally described the species the following year.
Conservation
The species is listed as Vulnerable on the 2006 IUCN Red List of Threatened Species due to its somewhat restricted distribution.
Habitat
- Altitude
- 1,600–2,000 m
- Altitude Class
- highland
- Native To
- Sumatra
- IUCN Status
- Vulnerable
Taxonomy
- Described
- 1973
- Authority
- Sh.Kurata
Cultivation
- Difficulty
- intermediate
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