All species › Caryophyllales › Tropical pitcher plant family › Nepenthes nebularum
Nepenthes nebularum
'Of the clouds', the name means: Nepenthes nebularum was found in a cloud forest so often shrouded in mist that the first observer could hardly see the plants. In September 2011 Stewart McPherson, on a mountain expedition in south-eastern Mindanao, saw black, pitcher-plant-like shapes high in the trees, but the fog prevented a proper look. Expeditions in 2012 led by the Filipino botanist Wally Suarez found a colony after three attempts, and the photographs showed it was something other than Nepenthes truncata or Nepenthes robcantleyi. In 2016 Geoff Mansell and Suarez described the species.
No photograph of this species under a Creative Commons licence or in the public domain is in the guide yet.
Identification
A robust rosette with a short stem, up to sixty centimetres across; in low light the stem elongates to a metre. The stem is round and up to one and a half centimetres thick. Mature leaves are large and broad, to 16.5 cm long and 15 cm wide, with a broadly truncate tip and four to six conspicuous longitudinal nerves on each side, on a petiole of twelve to fifteen centimetres. Pitchers of mature plants are cylindrical, 25 to 29 cm tall and up to 7.5 cm wide, with two prominent fringed wings one and a half centimetres wide and fringe of one to one and a half centimetres down the front. The peristome is very broad, up to about six to seven centimetres, with coarse ribs forming a sharp inverted V in section, two millimetres high and three millimetres apart. The lid is deltoid-ovate, about 7.5 by 5.5 cm, with a cordate base and undulate margin, a keel, a basal appendage and a half-cone appendage near the tip; keel and appendages are cream to yellow, the lid underside purple to maroon. Pitchers and tendrils are densely covered in rusty branched hairs.
Similar species
The species is close to Nepenthes robcantleyi and Nepenthes truncata, both of Mindanao. Nepenthes truncata has a narrower, rounded peristome and, in mature pitchers, no fringed wings left. Nepenthes robcantleyi is also dark and also has a very broad peristome, but is largely glabrous and glossy, whereas Nepenthes nebularum is densely rusty-hairy; lid shape and appendages differ too. The authors suggested that Nepenthes robcantleyi might be a natural hybrid of Nepenthes nebularum and Nepenthes truncata; DNA work is needed to confirm this.
The trap and how it works
A large pitfall with a strikingly broad, sharply ribbed rim. The peristome ribs are like an inverted V in section, two millimetres high, giving a pronounced slippery surface in wet weather. The broad fringed wings down the front are a walkway for crawling animals. The lid has both a basal appendage and one near the tip; the contrasting pale colour of keel and appendages against the dark lid underside coincides with where the nectar is offered. At two to three centimetres the spur is exceptionally long. Nothing has been published on prey.
Habitat and ecology
Submontane cloud forest up to about 1800 m (B1), where the plant grows mainly as an epiphyte on tall trees, sometimes on cliff faces. The mountains where it grows are wrapped in cloud much of the time. No lower limit has been published, so the elevation field is left empty.
Distribution and elevation
Endemic to Mindanao, and known from two separate mountains in the south-east of the island. Because the species is listed as Endangered on the Red List, this guide does not name the mountains. The label 'Mindanao, south-east' in our species list is correct.
- Native
Forms and variation
No varieties have been described. Young plants and plants in low light have different proportions: the stem elongates, and the pitchers of immature plants are smaller. The possible role of the species as a parent of Nepenthes robcantleyi is an open question; according to later observers artificial crosses of Nepenthes nebularum and Nepenthes truncata do not resemble Nepenthes robcantleyi, which rather argues for two closely related, separate species.
Where and when to see it
The sites are not public, and rightly so: this is one of the most coveted pitcher plants of the Philippines. Anyone walking in the cloud forest of south-eastern Mindanao can watch high in the trees for large, dark pitchers with broad fringed wings and a very broad, ribbed rim, often half hidden in mist. Keep your distance, take photographs, and share no coordinates.
Conservation status
In the data this guide relies on, the species is listed as Endangered. In 2016 the authors proposed Data Deficient, because populations in the remote forests are hard to count. Threats are the loss of submontane forest on Mindanao and the collecting pressure that a rare species attracts. Like all Nepenthes it is listed in CITES Appendix II.
Scientific name
Nepenthes nebularum | Mansell & Suarez, 2016
Nepenthes nebularum was described in 2016 by Greg Mansell and William Suarez, in "Nepenthes nebularum, a new species from Mindanao, Philippines" (Carnivorous Plant Newsletter 45(4): 132-139). South-eastern Mindanao, Philippines, documented from Mount Hafas and an undisclosed location, in submontane mossy forest up to 1,800 m elevation. The specific epithet alludes to the foggy habitat in which the species was discovered.
World Checklist of Vascular Plants (WCVP), via Plants of the World Online (POWO), Royal Botanic Gardens, Kew.