Nepenthes rajah
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Nepenthes rajah is a pitcher plant species from the pitcher plant family(Nepenthaceae). It is a carnivorous plant and only occurs in a small area on the island of Borneo . Their pitchers are one of the largest of all pitcher plants, which means they cancatch and digestnot only insects but also larger animals.
description
Vegetative characteristics
Nepenthes rajah is a shrub that, a wind comparable along growing in soil, but begins to climb as soon as it comes with an object in contact, at which the plant can interweaves. The shoot axis is up to three centimeters thick and is usually up to three meters long, but large specimens can reach up to six meters in length. Nepenthes rajah - unlike other species of the genus - does not form runners , but older plants form shoots at the base of the stem.
Due to its habitat , it is a very slowly growing plant species. It takes at least ten years for the first flowering and around a hundred years for the plant to reach its full size. All parts of young plants are covered with long, white-brown hair, but adult plants are hairless.
The leathery leaves are formed at regular intervals of about twenty centimeters along the stem axis . At each node there is a longitudinally grooved leaf stalk up to fifteen centimeters long, which merges into an up to 80 centimeters long and 15 centimeters wide, broadly linear-lanceolate leaf blade , which, however, in the strict sense of the word is just a reshaped leaf base . This is divided by a strong central rib , six to ten side ribs run from the beginning of the central rib, from these in turn branched veins run obliquely to the leaf margin. About three centimeters before the bluntly rounded end of the leaf base, the midrib emerges below it and turns into a tendril up to fifty centimeters long and up to three centimeters thick, which ends at the base of the can. Only the pot itself is then the actual leaf blade.
The pitchers from Nepenthes rajah (see picture above) are generally considered to be the largest of all pitcher plants, although the pitchers of the lesser-known species Nepenthes merrilliana and Nepenthes truncata as well as Nepenthes northiana and Nepenthes villosa can be similar in size.
Like many pitcher plants, Nepenthes rajah forms two different pitcher types ( pot dimorphism ), namely ground and air pitchers (see figure below). Air cans, which, in contrast to the cans lying on the ground, are found hanging freely in the upper regions of the plants, are very rare in Nepenthes rajah .
The urn- to egg-shaped ground pitchers are rust-red on the outside and light green to red on the inside. They grow up to 35 centimeters high and reach a diameter of up to 18 centimeters. From the top of the tendril up to the peristome (the edge of the jug opening), two wings up to 25 millimeters wide, lined with fringes at a distance of around two millimeters, run. The jug opening is elliptical , flattened and inclined at 45 ° from the outside to the inside. The peristome is up to four centimeters wide and curved five to six times on each side, the teeth thus formed are from top to bottom at a decreasing distance from one another. The peristome is made up of numerous fine, transverse ribs, which are 0.5 to 2 millimeters apart and bend as teeth beyond the peristome up to 5 millimeters into the inside of the pot.
A typical feature of the jugs is the large, domed lid. It is egg-shaped to broadly linear, heart-shaped at the base and bluntly rounded at the tip. It is up to 20 centimeters long and 13 centimeters wide and has a deeply sunk, keel-like central rib. At the base of the lid there is a spur up to two centimeters long, on its underside there are nectar glands that are visible to the naked eye. The inside of the pitcher is completely covered with 300 to 800 glands per cm², those of the upper half equipped for catching are extremely small, those of the lower, digesting half are significantly larger. The jugs contain up to two liters of liquid with a total volume of up to four liters.
The considerably smaller air cans of the plants are funnel-shaped, their wings are reduced to ribs and less intensely colored, but are otherwise the same as the ground cans.
Is known Nepenthes rajah and for their prey spectrum. Although the prey is usually made up of insects, rats have also been found repeatedly in their pitchers. It is believed that they slipped and drowned while trying to drink the jug liquid. For a long time, Nepenthes rajah was the only carnivore that could catch mammals at least occasionally , although there was no unequivocal documentary evidence of a mammal catch. In September 2006, the discovery of an already half-digested mouse in the calyx of a Nepenthes truncata in the Botanical Garden of Lyons made the thesis that Nepenthes rajah the only pitcher plant capable of catching mammals was relativized .
Flowers, fruits and seeds
Nepenthes rajah can bloom at any time of the year. Like all pitcher plants, it is dioecious , that is, a plant is either female or male, but never hermaphroditic. The inflorescence stalks, ten millimeters thick at the base and seven millimeters at the tip, are up to eighty centimeters long , the flower clusters up to forty centimeters long. The inflorescence is densely hairy in the initial stage, with increasing maturity the hairiness decreases, especially in the lower area, but remains close in the upper area, on the peduncle and perigone as well as on the ovary .
The numerous flowers are greenish white on the inside, brown on the outside and have a strong sweet smell. In the lower area of the inflorescence there are two flowers on each of the up to 25 millimeter long pedicels, which become increasingly shorter towards the upper area and only have a single flower. The up to eight millimeters long petals are elliptical to broadly linear and bluntly rounded, the petals of the female flower are narrower than that of the male. The stamens are three to four millimeters long, the anthers up to one millimeter long. The pollen of the plant is widespread up to ten kilometers, which favors the formation of hybrids (see below).
The yellow-brown capsule fruits are one to two centimeters long, thickened and slightly hairy, the seeds are thread-shaped, three to eight millimeters long and are spread by the wind ( anemochory ).
Nepenthes rajah as a living space
The pitchers of all pitcher plant species are not just traps that are used to catch and digest animals. They also offer shelter or even a habitat for many, sometimes specialized, animal and insect species. Since the shape and size of the pitchers differ just as much as the areas of the species, there are numerous organisms that specialize in individual species, as is the case with Nepenthes rajah . The pitcher liquid is home to the larvae of two mosquito species named after it , namely Culex rajah and Toxorhynchites rajah , but in addition to these there are also unspecialized larvae of the species Culex jenseni , Uranotaenia moultoni and an as yet undescribed species of the genus Tripteroides .
Some species of monkeys, including goblin lemurs , are known to slit open the side of the jug and feast on the contents of the jug.
Distribution and habitat
Nepenthes rajah is endemic to the rainforest areas of Kinabalu and neighboring Tambuyukon on Borneo in the northeast of the island .
Nepenthes rajah is a specialist who settles exclusively on thin, nutrient-poor soils on ultra-basic rock with a high content of magnesium , nickel and chromium . The last two metals are poisonous for most plants, but Nepenthes rajah is resistant to them and can therefore occupy this ecological niche with little competition. The plants grow on open, loose grass soils that are exposed to heavy rainfall, but which run off again extremely quickly due to the soil's inadequate ability to store water. They are often found accompanied by sedges ( Carex ).
Nepenthes rajah is a so-called highland species, as it only occurs at an altitude of 1500 to 2650 m above sea level. At these altitudes, temperatures can drop to freezing at night, and temperatures rarely exceed 25 ° C during the day. The relative humidity fluctuates from 65% during the day to 95% at night. These factors can also fluctuate greatly during the day, since high temperatures and, depending on these, lower humidity are only caused by intense solar radiation. Due to (frequently occurring) cloud cover, the temperature then falls and the humidity rises rapidly; an effect that is favored by the open vegetation and the increasing height. In addition, the habitats are exposed to strong winds and heavy rainfall, the average annual rainfall is 3000 mm.
Systematics
Nepenthes rajah is very little variable as a species, there are no subspecies, varieties or forms, and because of its unmistakable nature, there have never been any synonyms . The species was previously isolated in the genus without any close relatives, but in 1998 a new species was discovered in the Philippines , which could be related to Nepenthes rajah , especially according to can morphological aspects . The species was first described as Nepenthes mantalingajanensis in 2007, after it was long known as Nepenthes spec. Palawan 1 had been passed. Since a molecular genetic investigation of the genus is still pending, this method has not yet been able to provide any more detailed information about the exact position of Nepenthes rajah within the genus.
Natural hybrids
Nepenthes rajah hybridizes with some other pitcher plant species, this is favored by the relatively wide blowing of the pollen and the year-round flowering time. Hybrids with all other pitcher plant species occurring on the Kinabalu have been proven (with the exception of Nepenthes lowii ).
The following natural hybrids are currently known:
- N. edwardsiana × N. rajah
- N. fusca × N. rajah
- N. macrovulgaris × N. rajah
- N. stenophylla × N. rajah
- N. tentaculata × N. rajah
- N. × alisaputrana Adam & Wilcock (1992) [= N. burbidgeae × N. rajah ]
- N. × kinabaluensis S. Kurata , nom. nud. (1976) [= N. villosa × N. rajah ]
The last two hybrids have been formally described and have their own names. Both are also capable of sexual reproduction, which is why they have been referred to as "stabilized hybrids" that may represent precursors to new species. This rank has already been discussed for them, but has not prevailed.
status
Nepenthes rajah has been classified by the IUCN as an endangered species (EN - B1 + 2e) and has been listed on Appendix 1 of the Washington Convention on Endangered Species since 1981 , the highest CITES protection level that prohibits any trade in wild plants. This had become necessary because their popularity with collectors meant that their holdings were over-collected, especially in the 1970s. Due to this protection, commercial offspring, the increased environmental awareness among collectors and the fact that a large part of the deposits are in the Kinabalu National Park , the stocks have now recovered, so that a downgrading to Endangered (VU) seems justified.
Botanical history
Nepenthes rajah was discovered by Hugh Low during his first ascent of Kinabalu in 1851 and described by Joseph Dalton Hooker in 1859 . Spencer St. John first found a rat, and thus a mammal, in one of the pitchers in 1862 . In 1878, Frederick William Burbidge first collected living specimens for the British company Veitch and Sons , which were offered to interested (private) gardeners from 1881 and were presented to the public for the first time the following year at the annual exhibition of the Royal Horticultural Society . However, because the cultivation conditions were very demanding, the fashionable interest in pitcher plants was generally lost again and with the decline of the Veitch company from 1905 onwards there were no more offspring, the plants gradually disappeared from human hands again, the last known plant of the time was the Irish National Botanic Gardens in Glasnevin , Ireland, but it did not survive either.
It was not until the 1970s that public interest in pitcher plants reawakened, especially due to the general increase in popularity of carnivorous plants. In particular, the book Nepenthes of Mount Kinabalu by Shigeo Kurata shifted the focus back to the types of Kinabalu, including Nepenthes rajah .
In their homeland, pictures of the plant are often used as postcard motifs and for advertising purposes for corresponding tourist destinations, especially the Kinabalu National Park . In 1996 Malaysia published a four-part series of stamps with motifs on the subject of pitcher plants, one of which was Nepenthes rajah .
etymology
The name "rajah" comes from the Malay language and means "king". The name was chosen in honor of the adventurer James Brooke , the first White Raja of Sarawak , which is why the name "Rajah Brooke's Pitcher Plant" is occasionally found in English.
literature
Large parts of the article come from the English-language article en: Nepenthes rajah in the version of June 1, 2006.
swell
- Charles Clarke: Nepenthes of Borneo. Natural History Publishing et al., Kota Kinabalu et al. 1997, ISBN 983-812-015-4 .
- Martin Cheek, Matthew Jebb: Nepenthaceae (= Flora Malesiana. Ser. 1: Spermatophyta. Vol. 15). Nationaal Herbarium Nederland, Leiden 2001, ISBN 90-71236-49-8 .
- Benedictus H. Danser : The Nepenthaceae of the Netherlands Indies. = Contributions à l'étude de la flores des Indes Néerlandaises. XV. In: Bulletin du Jardin de Botanique. Series 3, Vol. 9, No. 3-4, 1928, ISSN 0852-8756 , pp. 249-438, ( N. rajah -Text online ).
- Richard Ellis: Carnivores on Stamps and Currency. In: Carnivorous Plant Newsletter. Vol. 29, No. 3, 2000, ISSN 0190-9215 , pp. 90-92, ( online ).
- Masuhisa Tsukamoto: Two New Mosquito Species from a Pitcher Plant of Mt. Kinabalu, Sabah, Malaysia: Culex rajah and Toxorhynchites rajah (Diptera: Culicidae). In: Japanese Journal of Tropical Medicine and Hygiene. Vol. 17, No. 3, 1989, ISSN 0304-2146 , pp. 215-228, doi : 10.2149 / tmh1973.17.215 .
further reading
- -. Nepenthes Rajah JD Hooker. In: Garden flora . Vol. 32, 1883, p. 213 .
- -. Nepenthes Rajah. In: Curtis's Botanical Magazine . Vol. 131 = Series 4, Vol. 1, 1905, Tab. 8017 .
- Shigeo Kurata : Nepenthes of Mount Kinabalu (= Sabah National Parks Publication. 2, ZDB -ID 842893-1 ). Sabah National Parks Trustees, Kota Kinabalu 1976.
- Maxwell T. Masters: Nepenthes Rajah Hook. f. In: The Gardeners' Chronicle . NS Vol. 16, 1881, p. 492 .
- Anthea Phillipps: A Second Record of Rats as Prey in Nepenthes rajah. In: Carnivorous Plant Newsletter. Vol. 17, No. 2, 1988, ISSN 0190-9215 , p. 55 .
- Anthea Phillipps, Anthony Lamb: Pitcher-Plants of Borneo. Natural History Publications, Kota Kinabalu 1996, ISBN 983-812-009-X .
- Hugo Steiner: Borneo. Its Mountains and Lowlands with their Pitcher Plants. Trekking from 1992 to 2002. Toihaan Publications, Kota Kinabalu 2002, ISBN 983-40421-1-6 .
Web links
- Nepenthes rajah on FleischfressendePflanzen.de
- Nepenthes rajah in the Red List of Threatened Species of the IUCN 2013.2. Posted by: Clarke, C., Cantley, R., Nerz, J., Rischer, H. & Witsuba, A., 2000. Retrieved May 10, 2014.
