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Nepenthes krabiensis
In the Khao Pra-Bang Khram Wildlife Sanctuary in Krabi province grow two pitcher plants that were only named this decade. The first, Nepenthes rosea, was described in 2014. The second followed in 2016, when a Thai team described the plants on the summits of the sanctuary as Nepenthes krabiensis. According to its describers it is closely related to N. rosea, but it grows higher, often in limestone crevices, and has pitchers blotched red inside rather than pink.
Identification
A climbing plant with round stems 1.5 to 2.5 m long and 3.5 to 5 mm thick. The leaves are leathery and lanceolate, 12.4 to 19.3 cm long and 2.2 to 4.2 cm wide. Lower pitchers are green to orange outside with red stripes. Upper pitchers are light green, with red blotches across the inner wall, and as in related species slimmer and more funnel-shaped than the lower ones, which are broader below. The male inflorescence is long: 58.6 to 62 cm, with 97 to 130 flowers. No figures for the pitchers themselves were found in the summary of the description consulted for this guide; that measurement field is left empty.
Similar species
The closest relative is Nepenthes rosea, which grows in the same sanctuary but lower down, between about 450 and 520 m, on sand and humus in clearings and scrub. N. rosea has thinner stems (to 4 mm), pitchers with an often plain pink interior, and sometimes rosettes on the flowering stem. N. krabiensis grows higher, on the summits between 600 and 700 m, often in rock crevices, and has upper pitchers blotched red inside. Both belong to the group around N. thorelii, in which species boundaries are thin and several names are regarded by some taxonomists as synonyms.
The trap and how it works
A pitcher trap as in related species: lower pitchers standing on the ground or in rock crevices and catching walking prey, and upper pitchers hanging from the climbing stems and also catching flying insects. Nectar on the peristome and under the lid lures prey; a wet peristome makes the rim slippery. The red blotches inside the upper pitchers are striking when you look into the pitcher; whether they have a role in attraction has not been studied. On the summits, where the soil is thin and poor, the extra nitrogen from prey matters to the plant.
Habitat and ecology
Summit areas of the hills, on sandy or humus-rich soil, often in crevices in limestone rock, between about 600 and 700 m (R2, B5). The plants grow in the light, in openings among the rocks and in low vegetation on the summits. Limestone is an unusual substrate for the genus; on the summits of the sanctuary sand evidently lies on or beside the limestone, so the plant can root in thin soils in the crevices.
Distribution and elevation
Endemic to Thailand, and known only from the Khao Pra-Bang Khram Wildlife Sanctuary in Khlong Thom district, Krabi province, on the Thai peninsula, between about 600 and 700 m. That makes it one of the most restricted species of the N. thorelii group. The sanctuary lies in the lowlands of southern Thailand, where most of the original forest outside protected areas has already gone.
- Native
Forms and variation
No varieties or forms are distinguished. The species was described only in 2016, and little has yet been published on variation within the populations. Colour varies as in related species: lower pitchers green to orange with red stripes, upper pitchers light green with a varying amount of red blotching inside. Natural hybrids with N. rosea in the zone between them are conceivable, but are not mentioned in the sources consulted.
Where and when to see it
The Khao Pra-Bang Khram Wildlife Sanctuary in Krabi province is the only area. The sanctuary is well known to birdwatchers; for the summits a local guide and permission from the park authority are needed. On the summits, look among the rocks and in crevices for lower pitchers, and for light green upper pitchers in the low vegetation. The type was collected in July; in the wet season, roughly May to November, the pitchers are full grown, though trails are slippery then. Leave the rock vegetation undisturbed.
Conservation status
The species is not evaluated for the Red List (Not Evaluated) in the source this guide uses. What is known: as far as is known it occurs only in one wildlife sanctuary, on a few summits between 600 and 700 m, which means a very small range. The protection of the sanctuary is a plus; collection for trade and disturbance of the summits are the obvious risks. As a member of the genus it is listed in CITES Appendix II; international trade in wild plants requires a permit.
Scientific name
Nepenthes krabiensis | Nuanlaong, Onsanit, Chusangrach & Suraninpong, 2016
Nepenthes krabiensis was described in 2016 by Nuanlaong, Onsanit, Chusangrach and Suraninpong, in Thai Forest Bulletin (Botany) 44(2): 128-133. Krabi Province, southern Thailand, at 600-700 m elevation. The specific epithet derives from the name of Krabi Province, combined with the Latin suffix "-ensis", meaning "from".
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.