Drosera rotundifolia

Sundew (Drosera rotundifolia )

Called the carnivorous round leaf sundew (Drosera rotundifolia ), also heavenly dew, Lord spoon, spoon cabbage sky, Spölkrut or Widdertod, is a species in the family of sundew plants ( Droseraceae ). The type is all occurring in Germany sundews protected as by the Federal Wildlife Trade Regulation.

Description

The Round-leaved sundew is a perennial herbaceous plant. The plant appears from a winter bud, the so-called Hibernakel and forms a basal rosette which grows to a height of 5 to 20 cm. After flowering starts already in early autumn, a winter rest of the plant by re- forming a winter bud, and the leaf feeding completely. The focused less on nutrients rather than anchoring root system of the plant is weak and extends only a few inches deep.

The plants carry at 1-7 cm long petioles standing round, horizontally outstretched catch leaves with a diameter of 0.5 to 1.8 centimeters. The leaves are staffed by approximately 200 hair-thin reddish tentacles who retire at its end a sticky secretion that is used to catch the insects. These sheets of round leaf sundew catches mostly small insects such as mosquitoes and flies, but occasionally larger insects such as butterflies or dragonflies, the latter by means of multiple sheets at the same time.

Flower

The Round-leaved sundew flowers from June to August, one to two, up to 30 cm high, one-sided clusters of up to 25 white, nearly 1 cm, to 2 mm long pedicles seated flowers that open only when there is sufficient sunshine.

Fruit and seeds

Round-leaved sundew are often the by -pollination ( self-fertilization but possible) produces large amounts to about 1.5 mm long, spindle-shaped, brown - black seeds in ungefurchten capsules. Since the seeds are very small and light, they are usually spent by the wind to new locations.

Ecology

The Round-leaved sundew is a perennial, deciduous rosette plant and a Hemikryptophyt that can survive through winter buds achselbürtige. Its leaves are transformed to catch leaves. The glands are on emergences with special interconnects for the recorded materials. There is carnivory. The animals are trapped mainly serves the additional recovery of nitrogen compounds on nutrient salt -poor soils. The catcher leaves are stalked on the edge with long, irritable by proteins Drüsenzotten, occupied the so-called tentacles. These differ at their head a viscous, shiny, fragrant drops from, among others, Protein -cleaving enzymes and formic acid. In the center of the page there are short-stemmed digestive glands. Tiny insects, such as Mosquitoes are retained by the catch mucus. After about an hour the irritated tentacles move through a growth movement center of the sheet. Eventually, the entire leaf begins after about 2 hours einzukrümmen, so that further digestive glands can get in touch with the loot. After approximately 8-12 hours the process is completed. After several days, the digestion is completed and the laminae to be flat again. Only the exoskeleton of the prey is not digested.

The flowers are beginning mostly geschlossenblütig ( cleistogamous ). It was only later normal flowers are formed which are usually only open in the morning for a short time. Your pollen is in tetrads. Pollinators are small Diptera. Bloom time is from June to August.

The fruits are loculicidal capsules that survive the winter. The tiny, only 0.02 mg heavy seeds have no endosperm, reduced seedling and an inflated seed coat. This allows them to reach a flying distance over 10 km as granules flyer. This allows the rapid colonization of freed, even remote locations. Germination is probably only possible with the help of fungi. In addition, the seeds sprout in the light and frost germinator. Fruit ripening is from August to October. The Vegetative propagation is by leaf buds of dying leaves in damp moss ( Blattembryonie ).

Dissemination

The Round-leaved sundew is found almost everywhere in the northern hemisphere, from Europe to Asia to North America, even in Alaska and Greenland, the plant is located. The plant needs full sun locations on wet, nutrient-poor and lime-free soils with a pH between neutral 7 and acidic 3, accordingly, they usually grows in bogs or wetlands, where it divides into Torfmoosteppichen the bog hollows or as pioneer plants on a regular basis exposed peat and find clay soils. Due to the draining of peatlands and peat cutting the habitat of the round-leaved sundew is gradually slipping away.

System

At altitudes there is occasionally a dwarf form with smaller leaves and only 1-3 flowers ( Drosera rotundifolia f pygmaea Saelan ex HJELT, Drosera rotundifolia var gracilis nuisance. HULTEN ex ). Where it occurs together with Drosera anglica, they often hybridize to Drosera x obovata.

Etymology

The botanical name is derived from the German language as the shape of the leaves, the epithet rotundifolia means " rundblättrig ".

Use

Even before the realization that the Round-leaved sundew is carnivorous, was the plant in the 12th century by Matthaeus Platearius, an Italian doctor from the School of Salerno, described under the name " herba sole" as a medicinal herb against cough. Later, he was also used against any type of lung disease, tuberculosis, epilepsy or mental illness.

Even today sundew is used against cough in homeopathy, however, round-leaved sundew is the use of the fallen because of its status as a protected species in favor of imported Drosera madagascariensis and sundew species from breeding.

The Round-leaved Sundew was a " lus -na- feàrnaich " in the Scottish Highlands is a traditional dye for the color purple.

Others

1860 came Charles Darwin on a heath in Sussex on round-leaved sundew and the occurrence was amazed at the large number of captured insects. Darwin then began to examine the plant in terms of a possible Karnivorie closer and led over the years extensive series of tests on her through. Although the idea of ​​carnivory by plants was not new, but was unanimously rejected by botanists of the time.

With the 1875 present in English and the following year in German work " Insectivorous Plants" ( " Insectivorous Plants " ), he proved the existence of round-leaved sundew and carnivory for the same time for many other genera and species. So he broke through the established by Carl Linnaeus dogma that the Karnivorie " against the divine order of nature" is.

The Round-leaved Sundew was elected to the flower of the year 1992.