Nepenthes Rajah (8)

''Nepenthes rajah'' is a carnivorous pitcher plant species of the family Nepenthaceae. It is endemic to Mount Kinabalu and neighbouring Mount Tambuyukon in Sabah, Malaysian Borneo. ''Nepenthes rajah'' grows exclusively on serpentine substrates, particularly in areas of seeping ground water where the soil is loose and permanently moist. The species has an altitudinal range of above sea level and is thus considered a highland or sub-alpine plant. Due to its localised distribution, ''N. rajah'' is classified as an endangered species by the IUCN and listed on CITES Appendix I.

The species was collected by Hugh Low on Mount Kinabalu in 1858, and described the next year by Joseph Dalton Hooker, who named it after James Brooke, the first White Rajah of Sarawak. Since being introduced into cultivation in 1881, it has always been a sought-after species, although costly and hard to cultivate. Tissue culture has allowed it to become more widespread in cultivation.

''N. rajah'' is best known for the giant urn-shaped traps it produces, which can grow up to highHamilton, G. 2011. The Sabah Society. and wide.McPherson, S.R. 2009. ''Pitcher Plants of the Old World''. 2 volumes. Redfern Natural History Productions, Poole. These are capable of holding of water and in excess of of digestive fluid, making them probably the largest in the genus.

''N. rajah'' can trap mammals as large as rats.Phillipps 1988, p. 55. ''N. rajah'' occasionally traps small vertebrates such as frogs, lizards, and even birds. Insects, and particularly ants, are its staple prey. The pitchers are host to many other organisms, some so specialised that they cannot survive anywhere else, and are called nepenthebionts. ''N. rajah'' has two such mosquito taxa named after it: ''Culex rajah'' and ''Toxorhynchites rajah''. The species is able to hybridise in the wild with all other locally-occurring ''Nepenthes'' species.

Etymology

Joseph Dalton Hooker described ''Nepenthes rajah'' in 1859, naming it in honour of James Brooke, the first White Rajah of Sarawak.Kurata 1976, p. 61. 'Rajah Brooke's Pitcher Plant'Phillipps & Lamb 1996, p. 129. is an accurate, but seldom-used common name. ''N. rajah'' is sometimes called the 'Giant Malaysian Pitcher Plant'Gibson 1983. or simply 'Giant Pitcher Plant', although the binomial name remains by far the most popular way of referring to this species. The specific epithet ''rajah'' means "King" in Malay and this, coupled with the impressive size of its pitchers, has meant that ''N. rajah'' is often called the "King of ''Nepenthes''".Steiner 2002, p. 94.

Plant characteristics

''Nepenthes rajah'' is a scrambling vine. The stem usually grows along the ground, but climbs whenever it comes into contact with a suitable support. The stem is up to ) thick and may reach up to in length, although it rarely exceeds . The leaves are distinctive and reach a large size. They are leathery in texture with a wavy outer margin. The leaves are characteristically peltate, whereby the tendril joins the lamina on the underside, before the apex. The tendrils are inserted within below the leaf apex and reach a length of approximately .

Pitchers

The pitcher is a trap consisting of the main pitcher cup, covered by an operculum or lid. A reflexed ring of hardened tissue, the peristome, surrounds the entrance. ''N. rajah'' produces two distinct types of trap. "Lower" or "terrestrial" pitchers, the most common, are very large, richly coloured, and ovoid in shape. Exceptional specimens may be more than in length and hold of water and over of digestive fluid, although most do not exceed .Clarke 2001b, p. 7. The lower pitchers rest on the ground. They are usually red to purple on the outside, lime green to purple on the inside. Mature plants may in addition produce much smaller "upper" or "aerial" pitchers, which are funnel-shaped, and usually more colourful. The tendril attachment is normally at the rear of the pitcher cup. True upper pitchers are rare, as the stems rarely attain lengths greater than a few metres before dying off.

The peristome has a distinctive scalloped edge and is greatly expanded, forming a red lip around the trap's mouth. A series of raised ribs intersect the peristome, ending in short, sharp teeth that line its inner margin. The inner portion of the peristome accounts for around 80% of its total cross-sectional surface length. The huge, vaulted lid is a distinguishing feature of this species. It is ovate to oblong in shape with a distinct keel down the middle, and two prominent lateral veins. The spur at the back of the lid is approximately long and unbranched.

The plant has very large nectar- secreting glands covering its pitchers. The inner surface of the pitcher is wholly glandular, with .Danser 1928, 38.

Flowers

''N. rajah'' seems to flower at any time of the year. Flowers are produced in large numbers on inflorescences that arise from the apex of the main stem. ''N. rajah'' produces a very large inflorescence that can be , and sometimes even tall. The individual flowers of ''N. rajah'' are produced on partial peduncles (twin stalks) and so the inflorescence is called a raceme (as opposed to a panicle for multi-flowered bunches). The flowers are reported to give off a strong sugary smell and are brownish-yellow in colour. Sepals are elliptic to oblong and up to long. Like all ''Nepenthes'' species, ''N. rajah'' is dioecious, which means that individual plants produce flowers of a single sex. Fruits are orange-brown and long . A study of 300 pollen samples taken from a herbarium specimen (''J.H.Adam 2443'', collected at an altitude of ) found the mean pollen diameter to be ( SE = 0.3; CV = 7.0%).

File:Kinabalu Mesilau N. rajah upper pitcher plant 2.jpg, Mature plants with both lower and upper pitchers
File:nep rajah peltate.jpg, The peltate leaf attachment
File:Rajahpitcher3.jpg, A terrestrial pitcher
File:Nepenthes rajah 41 cm pitcher.jpg, The pitcher found on The Sabah Society's March 2011 trip to Mesilau
File:Kinabalu Mesilau N. rajah upper pitcher 3.jpg, A rare aerial pitcher
File:Nep rajah2 flower.jpg, Plant in flower

Carnivory

''N. rajah'' is a carnivorous plant of the pitfall trap variety. It is famous for occasionally trapping vertebrates, even small mammals. There exist at least two records of drowned rats found in ''N. rajah'' pitchers. The first observation dates from 1862 and was made by Spenser St. John, who accompanied Hugh Low on two ascents of Mount Kinabalu. In 1988, Anthea Phillipps and Anthony Lamb confirmed the plausibility of this record when they managed to observe drowned rats in a large pitcher of ''N. rajah''. In 2011, a drowned mountain treeshrew (''Tupaia montana'') in a ''N. rajah'' pitcher was reported. ''N. rajah'' occasionally traps other small vertebrates, including frogs, lizards and even birds, although these cases probably involve sick animals, or those seeking shelter or water in the pitcher, and certainly do not represent the norm. Insects, and particularly ants, comprise the majority of prey in both aerial and terrestrial pitchers.

Mutualism with mammals

''Nepenthes rajah'' has evolved a mutualistic relationship with mountain treeshrews (''Tupaia montana'') in order to collect their droppings. The inside of the reflexed lid exudes a sweet nectar. The distance from the pitcher mouth to the exudate is the same as the average body length of the mountain treeshrew. As it feeds, the treeshrew defecates, apparently as a method of marking its feeding territory. It is thought that in exchange for providing nectar, the faeces provide the plant with the majority of the nitrogen it requires.Walker, M. 2010
Giant meat-eating plants prefer to eat tree shrew poo
''BBC Earth News'', March 10, 2010. In ''N. lowii'', ''N. macrophylla'' and ''N. ;rajah'', the colour of the lower lid surface corresponds to visual sensitivity maxima of the mountain treeshrew in the green and blue wavebands, making the lid underside stand out against adjacent parts of the pitcher.Moran, J.A., C. Clarke, M. Greenwood & L. Chin 2012. Tuning of color contrast signals to visual sensitivity maxima of tree shrews by three Bornean highland ''Nepenthes'' species. ''Plant Signaling & Behavior'' 7(10): 1267–1270. Of the three species, ''N. rajah'' shows the tightest 'fit', particularly in the green waveband.

In 2011, it was reported that ''N. rajah'' has a similar mutualistic relationship with the summit rat (''Rattus baluensis'').Wells, K., M.B. Lakim, S. Schulz & M. Ayasse 2011. Pitchers of ''Nepenthes rajah'' collect faecal droppings from both diurnal and nocturnal small mammals and emit fruity odour. ''Journal of Tropical Ecology'' 27(4): 347–353. Greenwood, M., C. Clarke, C.C. Lee, A. Gunsalam & R.H. Clarke 2011. A unique resource mutualism between the giant Bornean pitcher plant, ''Nepenthes rajah'', and members of a small mammal community. ''PLoS ONE'' 6(6): e21114. Whereas the mountain treeshrew visits pitchers during daylight hours, the summit rat is primarily active at night; this may be an example of resource partitioning. Daily scat deposition rates were found to be similar for both mammalian species.

Other interactions with animals

Pitcher infauna

Although ''Nepenthes'' are most famous for trapping and digesting animals, their pitchers play host to a large number of other organisms (known as infauna). These include fly and midge larvae, spiders (crab spiders such as ''Henriksenia labuanica''), mites, ants, and even a species of crab, '' Geosesarma malayanum''. The most common and conspicuous predators found in pitchers are mosquito larvae, which consume large numbers of other larvae during their development. Many of these animals are so specialised that they cannot survive anywhere else, and are referred to as nepenthebionts.

The complex relationships between these various organisms are not yet fully understood. The question of whether infaunal animals "steal" food from their hosts, or whether they are involved in a mutually beneficial (symbiotic) association has yet to be investigated experimentally and is the source of considerable debate. Clarke suggests that mutualism is a "likely situation", whereby "the infauna receives domicile, protection and food from the plant, while in return, the infauna helps to break down the prey, increase the rate of digestion and keep bacterial numbers low".

Species specific

As the size and shape of ''Nepenthes'' pitchers vary greatly between species, but little within a given taxon, it is not surprising that many infaunal organisms are specially adapted to life in only the traps of particular species. ''N. rajah'' is no exception, and in fact has two mosquito taxa named after it. '' Culex (Culiciomyia) rajah'' and '' Toxorhynchites (Toxorhynchites) rajah'' were described by Masuhisa Tsukamoto in 1989, based on larvae collected in pitchers of ''N. rajah'' on Mount Kinabalu three years earlier. The two species were found to live in association with larvae of '' Culex (Lophoceraomyia) jenseni'', '' Uranotaenia (Pseudoficalbia) moultoni'' and an undescribed taxon, ''Tripteroides (Rachionotomyia)'' sp. No. 2. Concerning ''C. rajah'', Tsukamoto noted that the "body surface of most larvae are covered in ''Vorticella''-like protozoa".Tsukamoto 1989, p. 220.

Another species, ''Culex shebbearei'', has been recorded as an infaunal organism of ''N. rajah''. The original 1931 record by F. W. Edwards is based on a collection by H. M. Pendlebury in 1929 from a plant growing on Mount Kinabalu. However, Tsukamoto notes that in light of new information on these species, "it seems more likely to conclude that the species 'C. rajah''is a new species which has been misidentitied as ''C. shebbearei'' for a long time, rather than to think that both ''C. shebbearei'' and ''C. rajah'' n. sp. are living in pitchers of ''Nepenthes rajah'' on Mt. Kinabalu".

Pests

Not all interactions between ''Nepenthes'' and fauna are beneficial to the plant. ''N. rajah'' is sometimes attacked by insects which feed on its leaves and damage substantial portions of the lamina. Monkeys and tarsiers occasionally rip pitchers open to feed on their contents.

History and popularity

Due to its size, unusual morphology and striking coloration, ''N. rajah'' is a popular insectivorous plant. However, it remains a little-known species outside the field of carnivorous plants. Due to its specialised growing requirements, it is not a suitable houseplant and, as such, is only cultivated by hobbyists and professional growers. Its reputation for producing some of the most magnificent pitchers in the genus dates back to the late 19th century. ''N. rajah'' was first collected by Hugh Low on Mount Kinabalu in 1858. It was described the following year by Joseph Dalton Hooker, who named it after James Brooke, the first White Rajah of Sarawak. The description was published in ''The Transactions of the Linnean Society of London''.Hooker 1859.

Spenser St. John wrote an account of his encounter with ''N. rajah'' on Mount Kinabalu in his 1862 ''Life in the Forests of the Far East''. ''N. rajah'' was first collected for the Veitch Nurseries by Frederick William Burbidge in 1878, during his second trip to Borneo. Shortly after being introduced into cultivation in 1881, ''N. rajah'' proved very popular among wealthy Victorian horticulturalists and became a much sought-after species. A note in ''The Gardeners' Chronicle'' of 1881 mentions the Veitch plant as follows: "''N. rajah'' at present is only a young Rajah, what it will become was lately illustrated in our columns...". A year later, young ''N. rajah'' plants were displayed at the Royal Horticultural Society's annual show for the first time.Phillipps & Lamb 1996, p. 22. The specimen exhibited at the show by the Veitch Nurseries, the first of this species to be cultivated in Europe, won a first class certificate. In Veitch's catalogue for 1889, ''N. rajah'' was priced at £2.2 s per plant.

Dwindling interest in ''Nepenthes'' at the turn of the century saw the demise of the Veitch Nurseries and consequently the loss of several species and hybrids in cultivation, including '' N. northiana'' and ''N. rajah''. By 1905, the final ''N. rajah'' specimens from the Veitch nurseries were gone, as the cultural requirements of the plants proved too difficult to reproduce. The last surviving ''N. rajah'' in cultivation at this time was at the National Botanic Gardens at Glasnevin in Ireland, however this soon perished also.

File:Hugh Low.png, Hugh Low
File:Nepenthes rajah Life in the forests of the Far East.png, In ''Life in the Forests of the Far East'' in 1862
File:First Nepenthes rajah cultivated in Europe.jpg, The first ''N. rajah'' plant cultivated in Europe, in ''The Garden'', 1882

Recent popularity

''N. rajah'' is relatively well known in Malaysia, especially its native Sabah. The species is used to promote Sabah's Kinabalu National Park and features on postcards from the region. ''N. rajah'' has appeared on the covers of ''Nepenthes'' publications, including '' Nepenthes of Mount Kinabalu'' ( Kurata, 1976) and ''Nepenthes of Borneo'' (Clarke, 1997), both published in Kota Kinabalu. In 1996, Malaysia issued a series of four postage stamps including one of ''N. rajah''. ''N. rajah'' was featured in the first episode of '' Kingdom of Plants 3D'', a natural history series presented by David Attenborough.

Ecology

Kinabalu

''N. rajah'' is restricted to Mount Kinabalu and neighbouring Mount Tambuyukon, both in Kinabalu National Park, Sabah, Malaysian Borneo. Mount Kinabalu is a massive granitic dome structure that is geologically young and formed from the intrusion and uplift of a granitic batholith. At , it is by far the tallest mountain on the island of Borneo and one of the highest peaks in Southeast Asia.

''N. rajah'' grows exclusively on serpentine soils with high concentrations of nickel and chromium, toxic to many plant species. This means that it faces less competition for space and nutrients.

File:Mount kinabalu 01.png, Mount Kinabalu, Borneo
File:Kinabalu ultramafic soil.png, Ultramafic outcrops (yellow) in Kinabalu National Park (green)

Climate

''N. rajah'' has an altitudinal distribution of above sea level and is thus considered an (ultra) highland or Upper Montane plant. In the upper limit of its range, night-time temperatures may approach freezing and day-time maxima rarely exceed . Due to the night-time temperature drop, relative air humidity increases significantly, rising from 65 to 75% to over 95%. Vegetation at this height is very stunted and slow-growing due to the extreme environmental conditions that prevail. Plants are often subjected to fierce winds and driving rain, as well as exposure to intense direct sunlight. The relatively open vegetation of the upper montane forest also experiences greater fluctuations in temperature and humidity compared with lower altitudes. These changes are largely governed by the extent of cloud cover. In the absence of clouds, temperatures rise rapidly, humidity drops, and light levels may be very high. When cloud cover returns, temperatures and light levels fall, while humidity levels increase.

Conservation status

Endangered species

''N. rajah'' is an Endangered (EN – B1+2e) on the IUCN Red List of Threatened Species. It is listed on Schedule I, Part II of the Wildlife Conservation Enactment (WCE) 1997 and CITES Appendix I, which prohibits commercial international trade in plants collected from the wild. Many plants have been removed from the wild illegally, depleting some populations within Kinabalu Park in the 1970s. This led to the CITES listing in 1981.

The recent advent of artificial tissue culture, or more specifically ''in vitro'', technology in Europe and the United States has meant that plants can be produced in large numbers and sold at relatively low prices (~US$20–$30 in the case of ''N. rajah''). ''In vitro'' propagation refers to production of whole plants from cell cultures derived from explants (generally seeds). This technology has largely removed the incentive for collectors to travel to Sabah to collect the plant illegally, and demand for wild-collected plants has fallen. The conservationist Rob Cantley assesses the current status of plants in the wild as due mainly to habitat damage rather than actual theft of plants. The plants in the wild are further threatened by climate phenomena including El Niño; the 1997/98 event and subsequent drought had a catastrophic effect on the ''Nepenthes'' on Mount Kinabalu.

Restricted distribution

The Mesilau Nature Resort near the village of Kundasang is now the only place where visitors can hope to see this species in its natural habitat.Clarke 2001b, p. 38. Daily guided tours are organised. Almost all other populations are in remote parts of Kinabalu National Park, off-limits to tourists.

Other localities include the Marai Parai plateau, Mesilau East River near Mesilau Cave, the Upper Kolopis River, and the eastern slope of Mount Tambuyukon. On Pig Hill, ''N. rajah'' grows at 1950–2320 m and is sympatric with '' N. burbidgeae'', '' N. tentaculata'', and the natural hybrid '' N. × alisaputrana''.Thong, J. 2006. ''Victorian Carnivorous Plant Society Journal'' 82: 6–12.

Natural hybrids

''N. rajah'' hybridises with all the other ''Nepenthes'' species with which it is sympatric. Charles Clarke notes that the pollen of ''N. rajah'' can be transported as much as .A rare find: ''N. rajah'' nat. hybrid
Flora Nepenthaceae.

Cultivation

''N. rajah'' is a montane species or "highlander", growing at altitudes ranging from 1500 to 2650 m. As such, it requires warm days, with temperatures ranging (ideally) from approximately 25 to 30 °C,On the Cultivation of ''Nepenthes rajah''
/ref> and cool nights, with temperatures of about 10 to 15 °C. It needs a fairly humid environment to grow well. Values in the region of 75% R.H. have been recommended. In its natural habitat, ''N. rajah'' grows in open areas, exposed to direct sunlight. In the tropics, growers can utilise natural sunlight as a source of illumination. In temperate zones, a photoperiod of 12 hours, comparable to that of the tropics, is recommended. The plant produces an extensive root system, requiring a wide pot. The species can tolerate hard water though purified water is recommended by specialists. From trials carried out by a commercial nursery,micronutrient solutions appear to be beneficial. Actual fertilizers (containing N P K) were found to be damaging.

Common misconceptions

Several stories have been told about the species. One such example is the famous legend that ''N. rajah'' grows exclusively in the spray zones of waterfalls, on ultramafic soils. Although it is true that they will grow in such places, ''N. rajah'' is certainly not found solely in the spray zones of waterfalls. It is likely that the misconception was popularised by Shigeo Kurata's 1976 book '' Nepenthes of Mount Kinabalu'', in which he states that "''N. rajah'' is rather fond of wet places like swamps or the surroundings of a waterfall". Some ''N. rajah'' plants do indeed grow near waterfalls (as noted by Hugo Steiner, 2002) "providing quite a humid microclimate". Another myth is that it occasionally catches small monkeys and other large animals in its pitchers. Such tales can probably be explained as rodents being mistaken for other species.D'Amato 1998, XV.

Notes

References

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* Stace, C.A. 1980. ''Plant Taxonomy and Biosystematics''. Arnold, London.
* Steiner, H. 2002. '' Borneo: Its Mountains and Lowlands with their Pitcher Plants''. Toihaan Publishing Company, Kota Kinabalu. viii + 136 pp. 
* Thorogood, C. 2010. '' The Malaysian Nepenthes: Evolutionary and Taxonomic Perspectives''. Nova Science Publishers, New York.
* Tsukamoto, M. 1989. . ''Japanese Journal of Tropical Medicine and Hygiene'', 17 (3): 215–228.
* Yeo, J. 1996. A trip to Kinabalu Park. ''Bulletin of the Australian Carnivorous Plant Society, Inc.'' 15(4): 4–5.

External links

General

Focus: Rajah Brooke's Pitcher Plant

Die Karnivoren-Datenbank: ''Nepenthes rajah''

Cultivation

''N. rajah'' Cultivation Notes

Other

The International Plant Names Index: ''Nepenthes rajah''



IUCN Red List of Threatened Species: ''Nepenthes rajah''

Video about ''Nepenthes rajah''
from ''The Private Life of Plants''

{{Taxonbar, from=Q132973

Carnivorous plants of Asia
Coprophagous plants
rajah
Endemic flora of Borneo
Flora of Sabah
Threatened flora of Asia
Plants described in 1859
Articles which contain graphical timelines
Flora of Mount Kinabalu
Flora of the Borneo montane rain forests