Nepenthes bicalcarata
| Nepenthes bicalcarata | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Nepenthes bicalcarata |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Nepenthes bicalcarata | ||||||||||||
| Hook.f. |
Nepenthes bicalcarata is a carnivorous plant from the genus of pitcher plants ( Nepenthes ). The species occurs exclusively in Borneo . It is the largest species of the genus and is ecologically characterized by a symbiosis with ants .
description
Vegetative habit
Nepenthes bicalcarata is a perennial , evergreen and climbing subshrub whose stem axis can be up to 20 meters long, which makes it the largest species of the genus. There are often short side shoots at the base of older plants. The stem axis is cylindrical in cross-section, up to 1.8 cm thick and occasionally hollow, in the latter case with circular holes that have been eaten in by ants and used as an entrance. The internodes are between 0.5 and 8 inches long.
The hair on the leaves and stems is only weakly pronounced, on the other hand, on the pitchers and inflorescences, densely covered with short fluff and isolated hairs 1 to 2 millimeters long. With increasing age, the hair falls off, mature parts of the plant are almost hairless.
leaves
The spread, thick paper, stalked leaves are elongated-round-lanceolate and 20 to 65 centimeters long and 6 to 14 centimeters wide. The outermost end is notched and pointed to blunt, sometimes shield-shaped, the base of the leaf is wedge-shaped. The narrow, winged petiole encompasses three quarters of the trunk and is 4 to 12 centimeters long, occasionally the wings still run down the trunk to the next knot . In the area of the approach to the stem there are large bordered nectaries on the underside . On each side of the midrib there are ten or more side ribs, the numerous, pinnate-shaped veins in between, which reach almost to the leaf margin, are clearly recognizable.
The tendrils hang down and are 10 to 20 centimeters long for floor pitchers and 12 to 30 centimeters for air pitchers. The tendrils of the ground jugs, which are up to 12 millimeters thick, have a thin-walled area facing the jug, which is usually gnawed through by ants of the Camponotus schmitzii and serves as an access. The swelling behind it is hollowed out and then serves as a space for a small ant colony.
Pitchers
Like many pitcher plants, Nepenthes bicalcarata forms two different pitcher shapes (pot dimorphism), namely ground and air pitchers. In contrast to many other Nepenthes species, the inside of the pitcher is not coated with wax.
The green, bulbous, convex ground jugs, covered in orange to red by the hair, are up to 13 centimeters long and up to 6.5 centimeters wide. They have fringed and up to 2.3 centimeters wide wing strips. The fringes are 1 to 5 millimeters long and are 0.5 to 4 millimeters apart. On the surface of the jug there are nectaries, piled on the tendril, the side of the wings and on the back. The can opening is approximately circular. On the front it is horizontally level, towards the back it rises. The green, rarely red peristome (the wide collar around the can opening) is rolled up into a cylindrical shape on the outside, around 4 millimeters wide and flattened inward, ribs are recognizable, but only weakly pronounced. The inside of the pitcher has 3000 to 5000 glands per cm².
At the outermost point of the neck, two pointed, 1 to 2.5 cm long thorns bend down, which secrete nectar. The thorns sit directly under the kidney-shaped and significantly wider than long lid, which measures 3.5 to 6 by 4.7 to 6 centimeters. The lid is yellowish on the top, dark red or purple on the underside, especially towards the edge. The nectar glands, which are closer to the sides and are almost missing in the middle and at the base of the lid, are only slightly bordered, circular and measure 0.3 millimeters in diameter. The simple, bent back spur is flattened and occupied by glands, it is 10 to 20 millimeters long.
The air cans are oval and cylindrical, up to 13 inches long and 6 inches wide. They taper a little towards the can opening. Instead of the fringed wings of the ground pitchers, they have two simple, but clearly pronounced ribs that only change into a slight wing at the peristome. The lid reaches sizes of up to 4 by 10 centimeters in diameter.
Flowers and fruits
Like the other species of the genus, Nepenthes bicalcarata is dioecious , that is, there are purely male and female plants. The inflorescence is a loose, up to one meter long panicle on an inflorescence axis up to 40 centimeters long .
Female inflorescences are wedge-shaped, pointed, the lower branches measure up to 4 centimeters and are three-flowered at most, the highest branches are one or two-flowered, bracts are always missing. The bracts are lanceolate and around 4 millimeters long.
In male inflorescences, the inflorescence axis is up to 6 millimeters thick at the base. The inflorescence axes of the partial inflorescences are up to 10 centimeters long and usually carry four to fifteen flowers, nectaries are occasionally found near their approach. The flower stalks are up to 2.5 inches long. Occasionally stand on the flower stems of the lower half of the basal Teilinfloreszenzen bracts . The dark purple, almost black bracts are approximately circular, 5 millimeters long and 4 millimeters wide. The androphor is 1.5 to 2 millimeters long. The stamens have grown together to form a bare column and are shorter than the flower envelope . The head of the anthers measures around 1 by 1.5 millimeters.
The fruits are three-lobed capsule fruits , the lanceolate valves are up to 3 inches long and 0.5 inches wide.
Function and ecology of the pitchers
Catch principle and function
Insects of all kinds are attracted by the vivid colors of the pitchers and the nectar glands at the base of the lid and under the peristome. However, the surface of the peristome of the pitchers is finely grooved and extremely smooth, making it impossible for simple insect feet to hold on. As soon as the insect gets too close to the inner edge of the collar, it slips off and falls into the pot. Like all other Nepenthes species , Nepenthes bicalcarata is used to catch insects as a nutritional supplement . Their location is characterized by extremely low-nitrogen substrates (e.g. peat or sand ). Nepenthes bicalcarata compensates for this latent nitrogen deficiency by digesting its prey. Special enzymes in your digestive fluid, e.g. B. Peptidases break down the protein in the carcasses and make the nitrogen available. Other nutrients such as phosphorus and potassium are also removed from the animal tissue. The plant can now absorb and use this via special glands in the pitcher. Trapping insects gives Nepenthes bicalcarata an advantage over their accompanying flora, which has to compensate for the nutrient deficiency caused by the location.
symbiosis
In addition to catching insects, Nepenthes bicalcarata has entered into an unusual symbiosis with the ant species Camponotus schmitzi . This phenomenon was first described in detail by the naturalist Frederick William Burbidge in 1880. The symbiosis was scientifically documented and confirmed in a study from 1992 to 1998 by Charles Clarke.
The ants mentioned live in scattered colonies in special, hollowed-out thickenings in the transition area from tendril to jug. You can often tell whether a plant is colonized or not by a small, circular hole at the level of the thickening that the ants themselves have drilled. The animals nest in the chambers and defend the plant against a special predator (a weevil of the genus Alcidodes ). The ants prefer the air cans for colonization. They avoid the ground jugs because the frequent and heavy rains would flood the ground jugs and the penetrating water would destroy the ant nests. Camponotus schmitzi feeds primarily on the nectar excretions of the thorn-shaped growths. The ants themselves have so-called arolias ( adhesive flaps ) on their feet , with the help of which they can safely walk over the peristome, which is smooth for other insect feet . Camponotus schmitzi has additional properties: it dips into the jug liquid in order to fish out and eat larger prey. How it is supplied with oxygen during longer diving phases is still unclear.
distribution
.jpg)
Nepenthes bicalcarata is endemic to the island of Borneo in northwestern Kalimantan , Sarawak , Brunei and southwestern Sabah at altitudes from sea level to 950 meters.
At its main location, undisturbed peat swamp forests dominated by Shorea albida , it is common. This type of forest is characterized by waterlogged, acidic peat soils and at times has a relative humidity of up to 90%. This is where the plants reach their largest dimensions. It is also often found on the edges of the peat swamp forests and in the Kerangas , heather forests on white sandy soils. It almost always occurs together with Nepenthes ampullaria .
Systematics and botanical history
Nepenthes bicalcarata was described by Joseph Dalton Hooker in 1873 . The specific epithet “bicalcarata” is derived from the Latin words bi (“two”) and calcaratus (“spurred”) and refers to the two thorn-like projections on the jugs. The only known synonym is Nepenthes dyak , subspecies, varieties or forms have not been described.
The English naturalist Frederick William Burbidge brought the first living specimens of Nepenthes bicalcarata to Europe in 1879. He introduced the plant to the famous breeder PC Veitch , who included it in his Nepenthes cultures from Veitch Nursery . Although Veitch described the culture of the plant as "extremely problem-free", specimens of Nepenthes bicalcarata were considered a special rarity and were traded at even higher prices than, for example, Nepenthes rajah or Nepenthes northiana .
Web links
Individual evidence
- ^ A b c d e Charles Clarke: Nepenthes of Borneo. Natural History Publications et al., Kota Kinabalu et al. 1997, ISBN 983-812-015-4 , pp. 68-71.
- ↑ a b c d e f g h Benedictus H. Danser : The Nepenthaceae of the Netherlands Indies. = Contributions à l'étude de la flores des Indes Néerlandaises. XV. In: Bulletin de Jardin de Botanique. Series 3, Vol. 9, No. 3-4, 1928, ISSN 0852-8756 , pp. 249-438.
- ↑ a b c d e f g h i j k l m Martin Cheek, Matthew Jebb: Nepenthaceae (= Flora Malesiana. Ser. 1: Spermatophyta. Vol. 15). Nationaal Herbarium Nederland, Leiden 2001, ISBN 90-71236-49-8 , p. 41 f.
- ↑ a b Holger Florian Bohn: Biomechanics of insect-plant interactions in Nepenthes pitcher plants . Dissertation, Julius Maximilians University of Würzburg, 2007, (PDF; 5.6 MB).
- ^ A b Wilhelm Barthlott , Stefan Porembski, Rüdiger Seine, Inge Theisen: Carnivores. Biology and culture of carnivorous plants. Eugen Ulmer GmbH & Co., Stuttgart 2004, ISBN 3-8001-4144-2 .
- ↑ Waltraud Schulze, Wolf B. Frommer, John M. Ward: Transporters for ammonium, amino acids and peptides are expressed in pitchers of the carnivorous plant Nepenthes. In: The Plant Journal. Vol. 17, No. 6, 1999, ISSN 0960-7412 , pp. 637-646, doi : 10.1046 / j.1365-313X.1999.00414.x .
- ↑ Marlis A. Merbach, Georg Zizka , Brigitte Fiala, Dennis Merbach, Webber E. Booth, Ulrich Maschwitz : Why a carnivorous plant cooperates with an ant - Selective defense against pitcher-destroying weevils in the myrmecophytic pitcher plant Nepenthes bicalcarata Hook f. In: Ecotropica. Vol. 13, No. 1, 2007, ISSN 0949-3026 , pp. 45-56 .
- ^ Charles M. Clarke: The effects of pitcher dimorphism on the metazoan community of the carnivorous pitcher plant Nepenthes bicalcarata Hook. f. In: Malayan Nature Journal. Vol. 50, 1997, ISSN 0025-1291 , pp. 149-157.
- ^ Bert Hölldobler , Edward O. Wilson : The Ants. Belknap Press of Harvard University Press, Cambridge MA 1990, ISBN 0-674-04075-9 , pp. 530-534.
- ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Birkhäuser, Basel et al. 1996, ISBN 3-7643-2390-6 .
- ^ Messrs. Veitch's Nursery Nepenthes-House. In: The Gardeners' Chronicle . NS Vol. 16, 1881, pp. 598-599 .