Cobra lily
| Cobra lily | ||||||||||||
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Cobra Lily ( Darlingtonia californica ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Darlingtonia | ||||||||||||
| Torr. | ||||||||||||
| Scientific name of the species | ||||||||||||
| Darlingtonia californica | ||||||||||||
| Torr. |
The Kobralilie ( Darlingtonia californica ) is a präkarnivore plant and the only type of monotypic genus Darlingtonia from the family of Pitcher plants (Sarraceniaceae). It is closely related to the carnivorous pitcher plants ( Sarracenia ).
features
The cobra lily is an evergreen, perennial , herbaceous plant with a rhizome one to two centimeters in diameter. It grows very slowly, only after two to three years does it take on its typical shape and after seven to ten years it blooms for the first time.
root
The plants do not have a main root, but form numerous fine hair roots out of the rhizome.
Leaves / trap
The foliage of the plants, which drifts directly out of the rhizome, consists exclusively of the typical tubular leaves that form a loose rosette. The leaves are slightly conical and widen from the base. They are hollow and reach a height of 60 to 80 centimeters, occasionally up to a meter, and a wing bar extends over their entire length on the front of the leaf. At their upper end they are covered by a helmet-like hood, at the front end of which an inverted V-shaped appendage hangs down. Behind this "snake tongue" lies a small opening that points towards the ground and is surrounded by a peristome . The leaves are either upright or grow almost horizontally to the ground, so that the serpent's tongue touches the ground and, unlike the upright leaves, mainly attracts soil-dwelling insects. Each leaf is twisted up to 270 degrees, so that the opening and snake tongue point away from the rosette - presumably to attract prey better.
The leaves are divided into six zones: Zone 1 is the "snake tongue", Zone 2 is the peristome, Zone 3 is the hood, and Zones 4 to 6 are deeper-lying sections of the actual tube. Each of these zones has a function for which it is appropriately equipped when catching prey.
- Zone 1 : The serpent tongue . It is usually colored conspicuously red and has numerous nectaries on its back , both of which serve to attract the prey. A directional hair on the surface makes it easier for the insect to go towards the hose opening than to turn away from it.
- Zone 2 : The opening . It is formed by a peristome that excretes particularly large amounts of nectar and thus lures the prey from the appendage into the actual tube.
- Zone 3 : The hood . It covers the tube and the protruding opening, preventing the prey from escaping upwards. At its highest point, it is often provided with chlorophyll-free stains that allow outside light to pass through almost unhindered and look like windows. Captured prey now try to leave the trap through these "windows"; during these "escape attempts" they now fall into the upright tube.
- Zone 4 : Upper hose area . This section of the hose, which is located directly below the hood, is provided with a layer of wax and hairs pointing downwards. Both forces the prey further down.
- Zone 5 : Middle hose area . The downward hairs are particularly dense here, and there are hardly any wax stains.
- Zone 6 : Lower hose area . This zone is completely smooth and no longer equipped with any catching device, it is used solely for digestion. It contains the plant's digestive fluid, which the plant literally pumps into the tubes, reinforced after it has caught its prey. Due to the lack of a cuticle, the surface of the tube is able to absorb the nutrients that are released by a symbiotic bacterial fauna , but also by commensals .
Despite this elaborate trap construction, the cobra lily is not a particularly good prey catcher compared to its relatives, the pitcher plants. It is also not able to produce digestive enzymes itself , but relies on the decomposition of the catch by bacteria in the solution. The prey spectrum includes both flying and ground insects due to the two different leaf shapes (standing upright and lying on the ground).
blossoms
The inflorescence , which is covered with bracts and develops from May, is up to a meter high, so it only slightly towers above the traps, which is unusual for a carnivore; At the time of flowering, however, the traps are not yet active. The single, pendent, self-fertile , but weak protandric flower is unusually built: the yellowish-light green sepals are slightly longer than the purple petals . In 1994, however, an occurrence of around 30 individuals was discovered in which the petals are not purple, but of the same color as the sepals. These do not open, but form a kind of capsule that is only accessible to possible pollinators through small openings formed by bulges in the petals on the edge near the tip. The type of pollinators for which this complex flower is formed is still not clearly known, despite long-term observations of the species, spiders are probably involved, but the odor of the flower - which is unpleasant for humans - also suggests that flies are involved are.
Fruit and seeds
After pollination has taken place , the ovary gradually lifts so that the capsule fruit stands upright. The developed fruit is inverted egg-shaped and contains several hundred to over a thousand sand-colored, hairy seeds two to three millimeters in length about ten weeks after pollination , the embryo is quite large, endosperm is present. Their hair makes them buoyant and drifts away from the mother plant with the current ( bythisochory ).
Vegetative propagation
The rhizome of the plants forms runners , which can form large plexuses as the colony ages. Each node of the rhizome in turn can independently develop new roots and leaves. In many locations, the rate of reproduction by runners is considerably higher than that by seeds. In particularly nutrient-poor locations, the rhizome plexuses may also serve to exchange nutrients between the individual individuals in a colony.
distribution
The species is endemic to the northwestern United States . It is only found in western Oregon and northern California , a single occurrence on Chase Lake near Seattle in Washington state is considered anointed . It is mainly found in mountainous areas ( Cascade Range , Sierra Nevada , Klamath Mountains , Siskiyou Mountains , Trinity Mountains ) up to 2500 m above sea level, but in Oregon, under appropriate conditions, it also descends directly to sea level on the Pacific coast (e.g. in Florence, Oregon , where the only seven hectares large Darlingtonia Botanical Wayside is the only nature reserve in Oregon is dedicated to only a single species). The number of specified occurrences fluctuates between 200 and 250, which are fairly evenly divided between Oregon and California.
Habitats
Cobra lilies grow preferentially in locations with rocky subsoil (mostly serpentine ), low nutrient supply and high heavy metal content (to which the plants are tolerant). The occurrences are often dense and extensive, the largest known occurrence in the Siskiyou Mountains comprising several thousand plants. Frequent locations are wet meadows and moors , but also river banks or soils made of pure (lime-free) sand in pine forests . All locations face south or south-west and lie in zones of high precipitation (1000 to 2000 mm).
For the plant to flourish, a high level of cool groundwater and abundant flowing water with well- drained soil are important, which ensure the necessary cool root temperature. Just as important are open and sunny locations, which are actually guaranteed in the area of distribution through periodic fires. This type of plant is partially hardy and at this time lies under snow and ice in some locations. The species is found in company with peat moss , round-leaved sundew , butterwort , Pinguicula macroceras ssp. nortensis and panther lilies ( Lilium pardalinum ).
Endangerment and Status
The cobra lily has been listed in Appendix 2 of the Washington Convention on the Protection of Species (CITES) since 1981 , which means that the trade in wild plants is subject to approval and is strictly regulated. In addition, the species is also subject to different protection statuses at state, regional and local level; What all of these have in common is that they classify the species as not directly endangered, but as relatively vulnerable due to its small distribution area and the special location requirements.
The main endangering factors are mining activities (the area of distribution is often rich in nickel , chromium and cobalt ), logging activities, road construction as well as leisure and settlement pressure (the latter especially in Oregon), which destroys habitats as well as indirectly through the suppression of fires that act as natural mowing . The greatest threat up until the 1980s was the collection of the plants by traders or collectors; this has since been reduced considerably due to the various protected positions and the increased environmental awareness of collectors. After all, some occurrences are located in protected areas and are therefore to be regarded as safe.
Communities
Numerous insect species live in and on cobra lilies, some of them in very close communities. Common commensals are Metriocnemus edwardsii (a fly), Eperigone trilobata (a species of spider) and Sarraceniopus darlingtoniae , a species of mite that occurs exclusively in the tubes of cobra lilies .
Systematics
Within the genus there is only one species, with no further subspecies or varieties, but an albino form is known. In addition to morphological features such as the flower structure, the ability to regulate the level of digestive fluid in the tubes and the precarnivory , the area of distribution, which is isolated from the pitcher plants in the east and south of the USA and is considerably distant, serves to distinguish it from the closely related pitcher plants . The latter is also used as a confirmatory feature of the classification as a separate genus.
The phylogeny of the family has been little researched, molecular genetic studies have shown that the cobra lily is a sister taxon of the other two genera of the family:
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Botanical history
The plant was only discovered in 1841 in wet meadows south of Mount Shasta by William Dunlop Brackenridge, a member of a botanical expedition of the US government. The first description was in 1850 by John Torrey , but was not published until 1853, the botanical genus name (which they carried a great chance with a snake genus shares in the animal kingdom) refers to the American physician and botanist William Darlington (1782-1863), the kind of epithet on the first find in California.
In 1871 the cobra lily was cultivated in the Kew Gardens , today it can be found in many botanical gardens and private carnivore collections, occasionally also in alpine and rock gardens.
In the 1870s, Rebecca M. Austin was the first to research the cobra lily. For several years she conducted intensive field research and from 1875 to 1877 communicated her results in a letter to the botanist William Marriott Canby , who supported and encouraged her. However, her notes have only been published in part to this day.
In 1891 it turned out that the name Darlingtonia had already been given by de Candolle in 1825 for a mimosa plant . This made the name invalid, whereupon the genus was renamed from Greene to Chrysamphora . But after the genus, now known as Darlingtonia , was incorporated into the genus Desmanthus in 1954 , the way was virtually free and an ICBN commission allowed Chrysamphora californica to be renamed Darlingtonia californica because this was the more established one ( nomen conservandum ).
proof
- 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 .
- Guido J. Braem: Carnivorous Plants. Species and culture. 2nd, revised edition. Weltbild, Augsburg 2002, ISBN 3-426-66762-2 .
- Christine Leigh Elder: Reproductive Biology of Darlingtonia californica. 1997, (Arcata CA, Humboldt State University, Master's Thesis, 1997; digitized version (PDF; 2.33 MB) ).
- Aaron M. Ellison, Elizabeth J. Farnsworth: The Cost of Carnivory for Darlingtonia californica (Sarraceniaceae): Evidence from Relationships among Leaf Traits. In: American Journal of Botany. Vol. 92, No. 7, 2005, ISSN 0002-9122 , pp. 1085-1093, JSTOR 4126151 .
- Norman James Fashing: Biology of Sarraceniopus darlingtoniae. In: Phytophaga. Vol. 14, 2004, ISSN 0393-8131 , pp. 299-305, ( online ).
- Cobra Lily website
- Detailed website on the cobra lily in English
- Information on the plant from the US Fish and Wildlife Service
- Darlingtonia californica in the endangered Red List species the IUCN 2006. Posted by: Quick, D. Catling, P., Folkerts, G. Frost, C. Gardner, R., et al. , 2000. Retrieved May 12, 2006.
Individual evidence
Most of the information in this article has been taken from the sources given under references; the following sources are also cited:
- ↑ Randall J. Bayer, Larry Hufford, Douglas E. Soltis: Phylogenetic Relationships in Sarraceniaceae Based on rbcL and ITS Sequences. In: Systematic Botany. Vol. 21, No. 2, 1996, ISSN 0363-6445 , pp. 121-134, JSTOR 2419743 .
