Long-leaved sundew

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Long-leaved sundew
Long-leaved Sundew (Drosera anglica)

Long-leaved Sundew ( Drosera anglica )

Systematics
Eudicotyledons
Nuclear eudicotyledons
Order : Clove-like (Caryophyllales)
Family : Sundew family (Droseraceae)
Genre : Sundew ( Drosera )
Type : Long-leaved sundew
Scientific name
Drosera anglica
Huds.

The long-leaf sundew ( Drosera anglica , syn .: Drosera longifolia ), also long-leaf sundew or English sundew , is a species from the genus sundew ( Drosera ), a genus of carnivorous plants . It is one of the only three species that also occur in Central Europe.

description

The long-leaved sundew is a perennial, herbaceous plant and forms an upright rosette. The root system of the plant, which is less focused on nutrient supply than on anchoring and water absorption, is weak and only reaches a few centimeters deep.

The leaves of the plants are between 35 and 95 millimeters long. The oblong to linear spatulate leaf blade is only 15 to 35 millimeters long and 2 to 5 millimeters wide and - typically for the genus - covered with reddish tentacles. It mainly catches flies with its leaves, but smaller butterflies or dragonflies are also occasionally caught; within minutes the tentacles bend onto the muzzle, followed by the leaf blade itself within hours, and only after the digestive process has the leaf unrolled again.

The long-leaved sundew blooms from June to July. The flower stalks, which are up to 20 cm high, have a wrap , the five-fold flowers of which open individually. The white petals are 8 to 12 millimeters long and can be both externally and self-pollinated .

After flowering and the formation of capsule fruits with numerous, egg-shaped and 1 to 1.5 millimeter long, black seeds, the plant goes into hibernation in early autumn by pulling in the leaves and forming a winter bud, the so-called hibernacle which it then drives out again the following spring.

At high altitudes, the long-leaved sundew forms an altitude form with smaller leaves and short inflorescences with 1–3 flowers.

Where the species occurs together with the round-leaved sundew, the common hybrid Drosera × obovata Mert is often found . & WDJ Koch . This cross is often confused with the pure species and can be recognized by the inverted egg-shaped leaves, a capsule that is shorter than the sepals and their sterility.

Chromosome number

The number of chromosomes is 2n = 40.

distribution

Worldwide distribution of Drosera anglica

The long-leaved sundew occurs around the globe in the temperate zones of the northern hemisphere , making it one of the most widespread types of sundew in the world. In some places the species penetrates further south, for example in southern Europe, Japan, California and even on the Hawaiian island of Kauai (the occurrences there are smaller in habit and do not form hibernacles).

Locations at up to 2000 m above sea level are known worldwide, in Germany a subalpine site in the southern Black Forest in the Feldseemoor at 1100 m above sea level was noted as one of the highest sites , where the winter frosts begin in October and end in May. In the Allgäu Alps, it rises to an altitude of 1000 meters in two places in Bavaria.

Along with the round-leaved sundew ( Drosera rotundifolia ) and the middle sundew ( Drosera intermedia ), it is one of three Central European representatives of its genus.

In Germany, long-leaved sundew can even be found in calcareous spring bogs in the Alpine foothills. Many sites once existed in northwest Germany, but there the species has experienced a sharp decline in recent years and is now threatened with extinction. Drosera anglica is the rarest of the native Drosera species in Germany and therefore particularly worthy of protection.

Hazard and protection

The long-leaved sundew is endangered in Germany (Category 2) and is under nature protection.

Habitat and socialization

Preferred locations are full sun, submontane and montane raised bogs, intermediate bogs and flat bogs, on waterlogged soils, mostly associated with peat moss . Unusually for a sundew, the plant is relatively lime-tolerant. The plants are (with the exception of the Hawaiian stocks) hardy and tolerate longer periods of frost. The long-leaved sundew occurs in Central Europe in societies of the order Scheuchzerietalia, more rarely those of the association Caricion davallianae.

evolution

Because in addition to the long-leaved sundew with its chromosome number of 2n = 40 all North American sundews have a chromosome number of 2n = 20, struck CE Wood 1955 provides that the Langblättrige sundew on a amphidiploids hybrids from the round-leaved sundew and Drosera linearis back, molecular genetic studies ( Rivadavia et al., 2003) support this thesis, as do the occasional (sterile) natural hybrids of both species in their morphological similarity to the long-leaved sundew.

Taxonomy

According to the Melbourne Code ICN Art. 56 & App. V the name Drosera longifolia L. (Sp. Pl. 1: 282. 1753) was declared invalid (nomen utique rejiciendum). The species must therefore now be called Drosera anglica Huds. (Fl. Angl. Ed. 2, 1: 135. 1778).

The following naturally occurring taxonomic levels have been described:

  • Drosera × woodii Gauthier & Gervais : Drosera rotundifolia × Drosera linearis with 2n = 20 ( sterile ), from which polyploidy gave rise to the fertile Drosera anglica
  • Drosera × linglica Kusakabe ex Gauthier & Gervais : Drosera anglica × Drosera linearis with 2n = 30 (sterile)
  • Drosera × obovata Mert. & WDJKoch : Drosera anglica × Drosera rotundifolia with 2n = 30 (sterile)

Since, according to the ICN, there can only be one name for each hybrid with the same parent species and, according to more recent findings, Drosera anglica itself is a hybrid (which was not yet known when describing the above names), backcrosses with the parent species are a taxonomic problem. Smarter therefore uses a different nomenclature:

  • Drosera anglica var. Anglica
  • Drosera anglica nothovar. woodii ( Gauthier & Gervais ) Smarter comb. & stat. nov
  • Drosera anglica nothovar. linglica ( Kusakabe ex Gauthier & Gervais ) Smarter comb. & stat. nov
  • Drosera anglica nothovar. obovata planchon (pro var.)

photos

  • Drosera anglica with common cup maids as prey

  • Drosera anglica in a raised bog in northwest Germany

  • Alpine dwarf form in a hillside moor in Carinthia

  • Hybrid of D. anglica x D. rotundifolia : Drosera x obovata

literature

The information in this article was obtained from the following sources:

  • Ludwig Diels : Droseraceae (= The Plant Kingdom . 26 = 4, 112, ZDB -ID 846151-x ). Engelmann, Leipzig 1906, p. 109.

Individual evidence

  1. ^ Heinrich E. Weber : Family Droseraceae sundew plants. In: Gustav Hegi : Illustrated flora of Central Europe. Pteridophyta, Spermatophyta. Volume 4: Angiospermae: Dicotyledones 2. Part 2, A: Heinrich E. Weber (Ed.): Spermatophyta, Angiospermae, Dicotyledones 2 (2). 3rd, completely revised and enlarged edition. Parey, Berlin et al. 1995, ISBN 3-8263-3016-1 , pp. 17-37.
  2. ↑ Thomas Huntke: Drosera x obovata MERT. & WDJ KOCH in Germany - Distribution and characteristics of a critical species. In: Floristische Rundbriefe. 39, 2005, ISSN  0934-456X , pp. 21-28 .
  3. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas. 8th, heavily revised and expanded edition. Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 , p. 479.
  4. ↑ Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings. Volume 1, IHW, Eching 2001, ISBN 3-930167-50-6 , p. 633.
  5. ↑ Thomas Huntke: The distribution of Drosera anglica Huds. in Lower Saxony then and now - the extent and causes of the decline of a raised bog specialist. In: Tuexenia. Vol. 27, 2007, ISSN  0722-494X , pp. 241-253.
  6. ↑ Carroll E. Wood, Jr .: Evidence for the hybrid origin of Drosera anglica. In: Rhodora. Vol. 57, No. 676, 1955, ISSN  0035-4902 , pp. 105-130 .
  7. ↑ Fernando Rivadavia, Katsuhiko Kondo, Masahiro Kato, Mitsuyasu Hasebe: Phylogeny of the sundews, Drosera (Droseraceae), based on chloroplast rbcL and nuclear 18S ribosomal DNA sequences. In: American Journal of Botany. Vol. 90, No. 1, 2003, ISSN  0002-9122 , pp. 123-130, JSTOR 4122732 .
  8. ^ Drosera in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved August 18, 2017.
  9. ↑ Jan Schlauer: A nomenclaturally acceptable rank for the sundew epithet 'obovata' . In: International Carnivorous Plant Society (ed.): Carnivorous Plant Newsletter . tape 37 , no. 4 , 2008, p. 118-119 ( carnivorousplants.org [PDF]).
  10. ↑ Jan Schlauer: Nomenclature of the Drosera anglica complex revisited . In: International Carnivorous Plant Society (ed.): Carnivorous Plant Newsletter . tape 39 , no. 2 , 2010, p. 46 ( carnivorousplants.org [PDF]).

Web links

Commons : Long-leaved Sundew  - Album with pictures, videos and audio files