page_title: Nepenthes rhombicaulis
section_title: Description
hierarchical_section_title: Nepenthes rhombicaulis / Description
caption_attribution_description: Nepenthes rhombicaulis from Simanuk-manuk, Sumatra.
context_page_description: Nepenthes rhombicaulis is a tropical pitcher plant endemic to Sumatra. The specific epithet rhombicaulis is formed from the Latin words rhombicus, meaning "rhomboid", and caulis, "stem". It refers to the cross-sectional shape of the stem internodes.
context_section_description: Nepenthes rhombicaulis climbs well and its stem is known to reach 35 m in length, making it one of the longest in the genus. Internodes are up to 20 cm long and 1 cm in diameter. They are usually rhomboid in cross section. The stem bears numerous sunken glands. The species has an extended rhizome which produces stems at irregular intervals.
  Leaves are sessile. The lamina is lanceolate-spathulate, up to 25 cm long, and up to 4 cm wide. It has an acute to sub-peltate apex and an amplexicaul base. Two to three longitudinal veins are present on either side of the midrib. Pinnate veins are oblique. Tendrils may be up to 15 cm long.
  Rosette and lower pitchers are ovoid to ventricose in the lower parts and cylindrical above. They reach 12 cm in height and 4 cm in width. A pair of fringed wings (≤3 mm long) runs down the front of the pitchers. The glandular region is restricted to the ovoid portion of the inner surface. Digestive glands occur at a density of 150 to 300 per square centimetre. The pitcher mouth is round and oblique. The peristome is sub-cylindrical to irregularly expanded and up to 5 mm wide. Its inner margin is lined with distinct, papery teeth up to 3 mm long. The lid or operculum is ovate and may bear a small apical appendage on its lower surface. Up to 100 nectar glands are present on the underside of the lid. A spur (≤5 mm long), which may be unbranched, bifid, or trifid, is inserted near the base of the lid.
  Upper pitchers have not been reliably recorded in the field and measurements for them have not been published. Based on Schmid-Höllinger's observations, they are ventricose in the lower parts and elongated above, becoming tubiform or slightly infundibuliform towards the mouth. The peristome is greatly reduced and bears smaller teeth. Wings may or may not be reduced to ribs. Several hundred nectar glands are present on the underside of the lid, although they are smaller than in lower pitchers.
  Nepenthes rhombicaulis has a racemose inflorescence. The peduncle and rachis both reach 20 cm in length, although the latter is usually shorter in female plants. Partial peduncles are two-flowered and lack bracteoles. Sepals are elliptical and up to 4 mm long.
  Most parts of the plant are virtually glabrous. The margins of the lamina are often lined with short red hairs. Inflorescences may have a sparse indumentum of minute hairs.
  The stem and lamina are green. Lower pitcher range in colour from dull green throughout to light red with purple blotches. The peristome may be light green to dark purple and is often darker around its outer margin. According to Schmid-Höllinger, upper pitchers are yellowish-green with pale red spots in the upper part and pitchers produced on offshoots from the climbing stem have clear red speckles throughout.
caption: A typical lower pitcher
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