Nepenthes mantalingajanensis — Vorstman's Guide to the Carnivorous Plants

Identification

A compact rosette or a short, rigid, erect plant thirty to sixty centimetres tall; climbing stems have hardly been seen in the field. The leaves are broadly lanceolate, to 20 cm long and 6 cm wide, with an acute or obtuse tip, on a petiole to seven centimetres; the tendrils reach thirty centimetres and are green, yellow, orange or red. Lower pitchers are ovate to amphora-shaped, to 15 cm tall and 6.5 cm wide, with two fringed wings bearing filaments up to five millimetres. The peristome is loosely cylindrical and broad, to two centimetres, with teeth up to five millimetres on the inner margin. The lid is cordate with a rounded or pointed tip, up to five by four centimetres; the spur is narrow and up to eight millimetres. Pitchers are yellowish green or orange outside, yellow or orange inside and often darkly mottled; the peristome ranges from yellow to dark reddish purple and is often striped. Upper pitchers were not found in field study of hundreds of plants and are thus made rarely or never. The male flowers open yellow, later turn dark red and have a faint sweet scent.

Similar species

The closest relatives are the other mountain pitcher plants of Palawan, Nepenthes attenboroughii, Nepenthes deaniana, Nepenthes leonardoi and Nepenthes mira, and Nepenthes peltata of Mindanao. From those species Nepenthes mantalingajanensis differs in its smaller stature and narrower lamina with a usually acute tip. Each of the Palawan relatives is tied to its own mountain or ridge, so the site itself says a great deal: on Mantalingahan above 1700 m a small rosette plant with swollen, toothed pitchers is this species. The superficial resemblance to Nepenthes erucoides of Dinagat is attributed to similar environmental conditions, not relationship.

The trap and how it works

A pitfall that exists almost only as a ground pitcher. The swollen, amphora-shaped pitchers stand in or on the scrub litter, with fringed wings as a walkway; the broad peristome with its long teeth on the inner margin forms a slick, overhanging rim. In the related species of Palawan and Mindanao this broad, toothed peristome is a general feature of mountain species that catch mainly on the ground. In such ground pitchers the catch usually consists mostly of walking animals, but there are no published prey data for this species. That the plant makes no upper pitchers fits its low habit among scrub.

Habitat and ecology

Stunted upper montane forest and scrub between 1700 m and the summit at 2085 m (B1, R5), where the species is common on open slopes, usually in full sun. On the summit itself the plants are strongly stunted and grow among subalpine shrubs. The related species of Palawan and Mindanao grow on ultramafic soils, and the authors of Nepenthes erucoides compare it with the ultramafic mountain species of Palawan (R3); how strictly the species itself is tied to that soil has not been published. Where bamboo grows densely the species disappears: it is apparently outcompeted.

Distribution and elevation

Endemic to Mount Mantalingahan in southern Palawan. The label in our species list is correct. Herbarium data name the approach from Brooke's Point on the east coast. The species occurs from 1700 m to the summit.

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 have been described. Colour varies clearly: pitchers are yellowish green to orange, the peristome yellow to dark reddish purple and often striped, and the tendrils green, yellow, orange or red. Plants on the summit stay smaller and squatter than plants lower on the slopes. No natural hybrids are mentioned in the literature consulted.

Where and when to see it

Mount Mantalingahan lies within a protected landscape and is a long, hard trek through forest without a beaten route; an expedition requires permits, local guides and several days. Above 1700 m, on open slopes and in the scrub towards the summit, the species is common and grows in sun; look among the low shrubs for yellow to orange amphora-shaped pitchers with a broad, striped rim. There is no need to search in the dense bamboo.

Conservation status

The Red List assesses the species as Least Concern. The population is large, with hundreds of plants on open slopes, and the site is remote and protected: Mount Mantalingahan has the status of a protected landscape. Like all Nepenthes it is listed in CITES Appendix II.

Scientific name

Nepenthes mantalingajanensis | Nerz & Wistuba, 2007

Nepenthes mantalingajanensis was described in 2007 by Joachim Nerz and Andreas Wistuba, in "Nepenthes mantalingajanensis (Nepenthaceae), eine bemerkenswerte neue Spezies aus Palawan (Philippinen)" (Das Taublatt 55(3): 17-25). The holotype (J. Nerz & A. Wistuba P001) is held at the herbarium of the Institut für Biologie I, University of Tübingen (TUB). The summit region of Mount Mantalingajan, the highest peak on Palawan island, Philippines, at 1,700 m elevation. The specific epithet derives from Mount Mantalingajan, to which the species is endemic, with the Latinised locational suffix "-ensis".

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