Nepenthes lamii — Vorstman's Guide to the Carnivorous Plants

Identification

In the strict sense adopted after 2011, a compact plant: upright to half-reclining stems, often branched at the base, to about 45 cm tall and up to a centimetre thick. The stem is always red, dark olive-green in shade. The leaves are thick and leathery, broadly elliptic, from 5 cm on juvenile rosettes to 18 cm on mature shoots, sessile and clasping, the blade held in a V. Lower pitchers are wholly obovate, 3 to 8 cm tall, with an almost round mouth tilted up to 45 degrees and a terete peristome 4 to 6 mm wide. Upper pitchers are narrowly funnel-shaped below and swollen above, usually about 12 cm tall and 6 cm wide, exceptionally 20 by 9 cm, with a peristome to 12 mm. Young parts bear short pale brown to golden hairs; mature leaves are nearly glabrous.

Similar species

The closest relative is Nepenthes monticola, included in this species until 2011. That species is a true climber to four metres with angular stems, has lower pitchers with a distinct waist, and grows lower, between about 1400 and 2620 m, in mossy montane forest. Nepenthes lamii in the strict sense is compact, largely upright, with red stems and more bulbous pitchers, and grows above the treeline. From Nepenthes vieillardii, with which it was once confused, it differs in the near absence of hairs on mature parts and in the much higher density of nectar glands beneath the lid. Nepenthes maxima occurs on the same mountain and has far larger, cylindrical upper pitchers.

The trap and how it works

A pitfall trap adapted to a cold, windy climate. Lower pitchers are small and bulbous and often lie among grass, moss and stones; they catch what walks over the ground. Upper pitchers are larger and hang slightly higher in the low vegetation. As throughout the genus, the lure lies mainly on the peristome and beneath the lid, where nectar glands sit; older descriptions of the species in the broad sense give a density of 1500 to 2000 glands per square centimetre under the lid, exceptionally high for the genus. Insects walking on the wet peristome slip into the fluid, where they drown and are digested. Little has been published on prey composition at this altitude; at low temperatures insects are less active, and a strong lure per pitcher then makes sense.

Habitat and ecology

Rocky, largely inorganic soils above the treeline, mostly on ultramafic rock, at about 3200 to 3250 m according to the emended description (R5, R3). It is one of the most extreme habitats in the genus: above 3200 m night temperatures around 4 °C are common and on the highest slopes it can freeze, while strong winds keep the plants low. The vegetation consists of montane scrub, grasses and open patches with little else. The plants grow terrestrially there, often in full sun, and under those conditions are strongly stunted and red.

Distribution and elevation

Endemic to the central range of the Indonesian province of Papua, on New Guinea. The emended description gives the upper reaches of Doorman Top as its locality; there Lam collected his material in 1920, including at 3250 m, and a collection from 3520 m on the summit itself is often cited as the highest record for any Nepenthes. Our own species list names Puncak Trikora; the literature consulted does not give that mountain as a locality for the species in the strict sense. Older records from lower elevations, around 1460 m and near the mining town of Tembagapura, largely concern the plants now called Nepenthes monticola.

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 3 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, not even with Nepenthes maxima, which occurs on the same mountain. Visible variation mostly follows site and altitude: the higher and more open, the smaller, stockier and redder the plant. Lower pitchers are usually reddish with darker speckles and a white to pale orange interior; upper pitchers are yellowish, sometimes with orange or red, and white to cream inside. Anyone who takes the species broadly and includes Nepenthes monticola will see more variation than exists in the strict sense.

Where and when to see it

This is one of the least accessible pitcher plants in the world. The sites lie in remote high mountains in the centre of Papua, without roads, and expeditions need long preparation, permits and local guidance. Allow for altitude sickness, cold, rain and sudden fog. Search not in the forest but above it: among stones and low scrub on open, windswept slopes. The plants are small and red and stand out less among moss and rock than one might expect. Anyone who finds a climbing pitcher plant with yellowish upper pitchers lower in the mountains is probably looking at Nepenthes monticola.

Conservation status

Assessed on the Red List as Least Concern. Population sizes are poorly known, and part of the available data concerns the species in the broad sense, including the plants now called Nepenthes monticola. The high-altitude sites are barely disturbed by people and have rarely been visited in decades, which protects the species but also limits knowledge of it. As a member of Nepenthes it is listed in CITES Appendix II, so international trade in wild plants requires a permit. A possible long-term threat is climate warming, which leaves high-mountain species little room to move upward.

Scientific name

Nepenthes lamii | Jebb & Cheek, 1997

Nepenthes lamii was described in 1997 by Matthew Jebb and Martin Cheek, in their revision "A skeletal revision of Nepenthes (Nepenthaceae)" (Blumea). The type material (from the Lam 1637 series) was collected on 17 October 1920 during the Van Overeem Expedition, on the slopes of Doorman Top (Mount Anggemuk), West Papua, at approximately 3,250 m elevation; both holotype and isotype are held at Herbarium Bogoriense. The slopes of Doorman Top (Mount Anggemuk), West Papua, Indonesia, at approximately 3,250 m elevation. The specific epithet honours the Dutch botanist Herman Johannes Lam, who collected specimens of this species during the Van Overeem Expedition of 1920.

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