Aldrovanda vesiculosa

Aldrovanda vesiculosa habit

The water trap ( Aldrovanda vesiculosa ), also Wasserhade or Blistered Aldrovandie, is a carnivorous plant in the family of sundew plants ( Droseraceae ). The water trap is a water plant.

The genus Aldrovanda is monotypic, that is, it has only one species However, there are extinct species of the same genus. Within the species, there are significant geographical differences ( as known eg the Australian form neither a winter rest by Turionen, nor is frost-hardy ).

Features

The water trap is a perennial, herbaceous freshwater plant. It is rootless, only the seedling has a rudimentary root, but dies early.

Habit

The plant is about 10 to 30 cm long. Along the stem axis are in short intervals in wirtelförmiger arrangement of five to nine 2 to 3 mm long catch leaves on a petiole, however, characterizes the Diels as an "extended leaf base ." The leaf base contains several air-filled cavities, which provide most of the buoyancy of the plant. The plant grows at the one hand, and dies at the other end; under good conditions be formed as one or two whorls per day.

Trap

With their catch leaves, a folding case like a smaller version of the Venus Flytrap, the water trap will catch small animals, preferably water fleas, but also, for example, young mosquito larvae. At the edge of the traps are four to six conspicuous stiff bristles; also inside the trap is covered with fine hair with sensitive hairs. It is sensing hairs that cause the closing of the two halves of the leaf blade in a maximum of 1/50 second, where the fishing is only possible with warm water temperatures (from about 20 ° C). Has the trap once caught a prey, so this is decomposed with the help of digestive juices.

Flower

The small, white flower of the water trap rises on short stems above the water surface; it remains open only a few hours. The subsequent formation of the seed capsule, however, is again under water. The seeds germinate kryptokotylar, i.e., remain within the cotyledons of the seed and take its reserves, the so-called endosperm, on. However, the water trap flowers - at least in temperate conditions - rather rare.

Sprossenteilung

The water trap reproduces mostly vegetatively. To this end, the plant branches heavily during their growth phase. By the subsequent death of the main shoot arise independent individuals. Since the plant is vigorous, can so quickly many individuals arise.

Turionen

A second method of vegetative propagation, however, occurs only in winter-hardy forms, is called by turion during the winter strategy of the plant. Here dissolve at the end of the growing season Blattwirtel of the shoot tip and fall due to the heavy weight and emissions of gases to the bottom of the water. The Turionen are hardy to about -15 ° C. The new start of growth in spring Turionen rise up again and start again with the growth.

Distribution and habitat

The water trap is the most widely used Karnivorenart at all, because it is native to Europe, Asia, Africa and Australia. However, in all of its areas it is rare. The way spreads out over Epichorie: it adheres to the feathers of waterfowl, so they procrastinate in other waters. Thus we find the water trap heaped along bird migration routes.

The water trap requires very clean, shallow, bright and warm stagnant water, which are also low in nutrients and slightly acidic ( pH 6 ). It can be found floating freely between rushes or reeds, but also rice. With increasing compaction of the fouling of their range the falls then goes back and immersed in other places again. She is sensitive to attack by algae.

Hazard and status

In European countries, the water trap is rare, threatened with extinction or already extinct. It is often regarded here as the tertiary relic. 200 years ago, still could be detected 150 sites; currently are only just under forty known, mostly in Eastern and Southeastern Europe located (eg, 10 in Poland, 1 in Hungary, one in Romania, as well as a few in the former Yugoslavia, Bulgaria, Ukraine and Russia). Over the past 30 years, the kind died in Europe in France, Italy, Slovakia, Austria (Lake Constance) and Germany. The observed decrease in the water trap is generally due to man-induced eutrophication ( increasing nutrient supply ) due to their waters.

In Germany it is demonstrated again in Brandenburg and Worms; the local stocks are considered as angesalbt, it is officially extinct since 1986. Some stocks also exist in Switzerland, where it is not actually native; these sites date back to Ansalbungen from 1908. They are nevertheless strictly protected, because they are attributed to the self- extinguished in Germany stocks from Lake Constance among others.

In Asia, the species is in decline; around the turn of the millennium, the species is extinct as a wild form in Japan, proved she is still in Bengal.

In Australia, the incidence of falls are still undisturbed. You get there before in both tropical forms (eg to Darwin or Queensland ) and subtropical (eg, to Esperance).

About detailed locations of the plant in Africa, little is known. Reported occurrences stretching from East Africa to Central (Sudan, Uganda, Rwanda, Tanzania, Zimbabwe, Mozambique ) and South Africa (eg the Okavango Delta in Botswana ). Because of the relatively undisturbed African Flora and low agrarianization the continent a threat to the species is to be regarded there as unlikely.

In Australia and all European countries where it still exists, the species is strictly protected.

Paleobotany

Based on fossilized seeds and pollen finds allows the evolution of the genus traced far back. Mid-1980s, seed fragments of a species were found from the end of the Cretaceous period in what is now the Czech Republic, representing the oldest known ancestor of the genus and also the second oldest fossils of a carnivorous type at all. The plant splendens described as Palaeoaldrovanda was a contemporary of the dinosaurs and lived under tropical conditions.

The triggered by 65 million years ago at the Cretaceous - Tertiary boundary mass extinction did not affect the future prosperity of this genus. Almost twenty other species are known from the early Cenozoic. The separated already in the Eocene in the sections Aldrovanda, obliquae and Clavatae. Whether hot or cold periods followed, the species was always present with multiple types. Even in the Pleistocene, the presence of our previous ice age, can still be detected six species of which only A. vesiculosa survived to the present day.

Since due to the low mass of the plant only seeds or pollen are always preserved fossil, hardly can make a statement about the former shape of the plants. All the more significant was the unprecedented discovery of a fossil leaf of a 6 million year old Aldrovanda inopinata from the Miocene. This discovery was made in 1963 in Wacker village. The blade is very similar to today's type; an important difference, however, in the absence of sensory hairs in the center of the leaf blade.

Botanical history

Was discovered the falls in 1699 by Leonard Plukenet in India, which they called Lenticula palustris Indica. It was given its current scientific name in 1747 by Giuseppe Monti, who described Italian specimens and named in honor of the Italian scholar Ulisse Aldrovandi Aldrovandia vesiculosa. During the transfer of the name by Carl Linnaeus in 1753 but lost the first " i" in the name. Your first proof in Germany took place in 1846 in a pond at Pless ( Pszczyna ) in Upper Silesia, Emanuel Frederick House Leutner.

System

Charles Darwin introduced another distinction between the tropical and subtropical forms of water the case of the tempered form under the names Aldrovanda vesiculosa var australis or Aldrovanda vesiculosa var to verticillata. From this system have been abandoned; nowadays all water traps are managed as a taxon, despite different growth forms.

The closest relative of the water trap is morphologically similar Venus Flytrap.

Use

Like all carnivorous plants is the water trap object of interest from collectors. In the 1990s, the species was amplified added to collections after Australian types were imported whose tropical or subtropical habit enabled by a growing under uniform conditions without winter dormancy. Your permanent culture is, however, partly because of aquatic containment and their specific claims, it was still difficult.

A stylized water trap is the symbol of the German Society for Carnivorous Plants.