Nepenthes naga — Vorstman's Guide to the Carnivorous Plants

Identification

A climber to about 5 m, with a stem to 1 cm thick and internodes to nearly 15 cm, round to rhombic in cross-section. The leaves are stalkless, spathulate to oblong and leathery: on the rosette to 27 cm long and 7.8 cm wide, on the climbing stem to 16 by 6 cm. The rosette tendrils, to 41 cm, are peltately attached. Lower pitchers are ovoid below and cylindrical above, to 33.5 cm tall and 6.8 cm wide, with a peristome widening at the sides to nearly 6 cm and an ovate lid to 8.5 by 7.2 cm with a wavy margin. Upper pitchers are funnel-shaped below, then ovoid and cylindrical above, to 24 cm tall and 4.5 cm wide, with a peristome of about 1 cm. The lid carries a hooked crest at its base and a forked appendage of up to 1.5 cm just below the tip.

Similar species

Its closest relative is Nepenthes bongso, and many specialists believe N. naga falls within that species' variation; a recent synopsis of the Sumatran species (Biodiversitas) does keep it separate. From N. ovata and N. spathulata, which can also have broad peristomes and spathulate leaves, it differs in the forked appendage under the lid and the wavy lid margin. In the field that appendage is the decisive character: look into the lid from below. Without an appendage, or with an undivided one, the plant is a related species.

The trap and how it works

A pitfall with a pronounced luring apparatus. The forked appendage under the lid bears large nectar glands half a millimetre to a millimetre across, and the hooked crest at the lid base sits just above the mouth. An insect feeding on these glands stands over the opening. The lower-pitcher peristome is very wide at the sides, to nearly 6 cm, with teeth to 4 mm on the inner margin, and forms a large slippery surface around the mouth; in the upper pitchers it is narrow. The spurs are flattened with a forked tip. Nothing has been published on the prey.

Habitat and ecology

An epiphyte of mossy montane cloud forest (B1), at 1500 to 2000 m. The vegetation is dominated by trees of the beech family (Fagaceae) and ferns of the family Gleicheniaceae, with various montane shrubs. The plant roots in the moss on trunks and branches and climbs through the canopy; the rosette leaves and large lower pitchers form where it sits on a firm, mossy base. The climate is cool, almost always wet and often misty.

Distribution and elevation

Endemic to Sumatra, Indonesia, and known from a single small population in the Barisan range in the province of North Sumatra. Altitude: 1500 to 2000 m. The area given in our species list (North Sumatra) agrees with the description and the world checklist. How far the species extends in the range is unknown.

Recorded (one-degree cells)

Distribution based solely on records at GBIF (Global Biodiversity Information Facility), not on TDWG regions — those are often far larger than the actual range. The light halo is the area around a record, the dark core the record itself. The darker cells are 2 one-degree squares — roughly a hundred and ten kilometres — in which the species has been recorded, from all GBIF records. This is coarser than for most species because hardly any record of this plant carries an accurate coordinate: the locality of poached species is obscured at source. At this scale that obscuring disappears into the noise. The cells show where it has been seen, not where it occurs: an empty square means nothing.

Forms and variation

No varieties or forms have been described and no natural hybrids are known. The difference between lower and upper pitchers is large: lower pitchers over 30 cm tall with a very broad peristome, upper pitchers at most 24 cm with a narrow peristome and a funnel-like base of their own. Because some regard the species as a form of N. bongso, pre-2009 literature records of 'bongso' from this part of the range should be read with caution.

Where and when to see it

The species grows in the cloud forest of the Barisan range and can be reached only on a trek of several days, with a local guide and with permission from the villages. As an epiphyte, its pitchers often hang metres up in the mossy canopy: binoculars are more useful than a hand lens. Anyone who finds a pitcher within reach can look carefully at the underside of the lid without bending it; the forked appendage is visible to the naked eye. Collecting is prohibited and the population is small.

Conservation status

The Red List assesses the species as Vulnerable. The only known population is small and lies on unprotected land threatened by the spread of rubber plantations and by illegal plant collecting; striking new species are highly sought after by collectors. The montane forest above the farming zone offers some protection, but not formal protection. As a member of the genus, N. naga is listed in CITES Appendix II.

Scientific name

Nepenthes naga | Akhriadi, Hernawati, Primaldhi & Hambali, 2009

Nepenthes naga was described in 2009 by Pitra Akhriadi, Hernawati, Alfindra Primaldhi and Muhammad Hambali, in Reinwardtia 12(5): 339-342. The holotype was collected on 27 July 2007 at 1,500-2,000 m elevation in the Barisan Mountains, North Sumatra, and is held at the herbarium of Andalas University (ANDA), Padang, West Sumatra; an isotype is held at Herbarium Bogoriense (BO). The Barisan Mountains, North Sumatra, Indonesia, at 1,500-2,000 m elevation. The specific epithet is the Indonesian word for "dragon", referencing two features: the species' distinctive forked appendage on the pitcher lid and its notably large pitchers. The name also alludes to local folklore from the Barisan Mountains region about dragons historically said to inhabit the area.

World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.