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Nepenthes epiphytica
Many pitcher plants grow now and then as epiphytes, on branches instead of on the ground; this one does nothing else. Nepenthes epiphytica, described in 2011 by Alastair Robinson, Joachim Nerz and Andreas Wistuba, is called an obligate epiphyte in its description: a plant that, as far as is known, never roots in the soil. It comes from the limestone country of East Kalimantan and was long regarded as a form of the widespread Nepenthes fusca. It is a small, slender plant with long, narrow lower pitchers and broad funnel-shaped upper ones.
No photograph of this species under a Creative Commons licence or in the public domain is in the guide yet.
Identification
A small climbing shrub of at most two metres, with a thin stem up to 5 mm thick that may be green to reddish purple. The rosette leaves are coriaceous, lanceolate to narrowly elliptic, to 15 cm long and 5 cm wide, with distinct longitudinal veins and a petiolate base. The lower pitchers are strikingly narrow and cylindrical, to 20 cm tall and only 3 cm wide, with an oblique, ovate mouth and a cylindrical peristome to 6 mm; they are usually yellow or olive with red speckles. The upper pitchers have quite another shape: funnel-shaped, to 15 cm tall and up to 10 cm wide at the mouth, which is horizontal, with a broader peristome reaching 10 mm at the sides. They are yellowish green, with red stripes on the peristome.
Similar species
The species closely resembles Nepenthes fusca in the broad, old sense, in which it was formerly included; in the 1990s it was cited in the literature as N. fusca subsp. kostermansiana, a name never validly published. From the fusca group N. epiphytica differs in, among other things, its upper pitchers with their wide, horizontal mouth and its limestone habitat. Within the N. maxima complex, which also includes N. boschiana and N. platychila, it is the only strictly epiphytic member.
The trap and how it works
Both pitcher types are pitfalls with nectar on the peristome and under the lid, a peristome that becomes slippery, and digestive fluid below. In an epiphyte even the lower pitchers stand not on the ground but in moss and among roots on branches, so the usual division of labour between the 'ground trap' for crawling animals and the 'aerial trap' for flying insects is less sharp here. The long, narrow lower pitchers suit the capture of ants and other animals walking along branches, but no prey study has been published.
Habitat and ecology
Open forest on limestone at around 1000 m (R2, B5). The plant grows only as an epiphyte on trees and shrubs in this open forest, where light reaches down to the lowest branches. Limestone is an unusual substrate for Nepenthes, since most species prefer acid ground; an epiphyte, however, is little affected, because its roots sit in acid moss and humus on the branches, not in the lime-rich soil.
Distribution and elevation
Endemic to Borneo, in the province of East Kalimantan; it was described from Mount Nyapa in Berau Regency and is also known from neighbouring East Kutai. This agrees with 'Kalimantan' in the guide's own species list. The limestone country of Berau and East Kutai is extensive and little explored, so the species probably occurs at more sites.
- Native
Forms and variation
No varieties or wild colour forms have been described. Lower-pitcher colour ranges from yellow to olive green, with more or fewer red speckles, and plants in the sun often have redder stems. No natural hybrids have been published. Like all pitcher plants the species is dioecious: there are male and female plants, and both must be in flower for seed to set. The small, inconspicuous flowers are borne in racemes or panicles and are pollinated by insects; the seeds are light and dispersed by wind.
Where and when to see it
The limestone areas of Berau are better known for their caves and karst towers than for pitcher plants, and are visited from the coast. As the species grows only on trees, searching the ground is pointless: look at the moss on branches in open forest on the limestone slopes. The long, narrow lower pitchers often hang among epiphytic ferns and orchids. Take binoculars; many plants sit above eye level.
Conservation status
There is no IUCN assessment of this species (Not Evaluated). What is known: the range is small and lies in a region of East Kalimantan where limestone is quarried for cement and forest is giving way to plantations and mining. As an epiphyte the species also depends on the forest itself: where the trees go, the plant goes. As a member of Nepenthes it is listed in CITES Appendix II. For enthusiasts it is worth knowing that almost all species of the genus are now available through tissue culture; anyone wishing to grow a plant has no need of wild ones.
Scientific name
Nepenthes epiphytica | Robinson, Nerz & Wistuba, 2011
Nepenthes epiphytica was described in 2011 by Alastair Robinson, Andreas Nerz and Andreas Wistuba, published in Stewart McPherson's book New Nepenthes: Volume One (pp. 36-51). The Berau and East Kutai Regencies of East Kalimantan, Borneo, at approximately 1,000 m elevation. The specific epithet refers to this species' epiphytic habit, growing on other plants rather than in the soil.
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.