Prostrate St. John's wort

from Wikipedia, the free encyclopedia
Prostrate St. John's wort
Lower St. John's wort (Hypericum humifusum)

Lower St. John's wort ( Hypericum humifusum )

Systematics
Rosids
Eurosiden I
Order : Malpighiales (Malpighiales)
Family : St. John's wort family (Hypericaceae)
Genre : St. John's herbs ( Hypericum )
Type : Prostrate St. John's wort
Scientific name
Hypericum humifusum
L.

The low-lying St. John's wort ( Hypericum humifusum ), also called lying hard hay , is a type of plant from the genus St. John's wort ( Hypericum ) within the St. John's wort family (Hypericaceae). St. John's wort is the smallest species of the genus St. John's herbs ( Hypericum ). This species has prostrate stems and small flowers. It prefers forest clearings with soils poor in lime.

description

Illustration from Flora Batava , Volume 7
Radially symmetrical flower
The petals only slightly rise above the sepals, which are usually of different sizes. Both are covered with black glandular points.

Vegetative characteristics

St. John's wort is a graceful, annual to perennial herbaceous plant and only reaches heights of 5 to 15, sometimes 30 centimeters. It is characterized by a hollow, prostrate, creeping stem that appears thread-like and is almost two-edged. The leaves are arranged opposite one another. The simple, blue-green leaf blade is 5 to 15 millimeters long and narrow-elliptical.

Generative characteristics

The flowering period extends from June to September. Only a few (usually one to four) flowers are formed per plant. The relatively small flowers are radial symmetry and five-fold with a double flower envelope . The five lanceolate and entire sepals are unequal in size, short acuminate and black glandular. The five fresh yellow petals are 4 to 7 millimeters long. St. John's wort has only a few stamens .

The number of chromosomes is 2n = 16.

ecology

St. John's wort is a winter or summer annual, and in the mild climate it is also a perennial creeping plant .

Mostly self-pollination takes place , in some cases there is also celestogamy . The seeds, which are difficult to wet, are presumably spread as rainworms and together with soil when stepped on.

Occurrence

The distribution area is limited to the meridional-temperate zones of Central Europe and England.

The pioneering Hypericum humifusum mainly colonizes short-lived muddy ground pioneer corridors and crawling and treading lawns. It can be found on moist, sandy to loamy fields, on damp roadsides and clearings throughout Germany. It is considered a moisture indicator. According to the ecological indicator values ​​according to Ellenberg , the species is specified as a penumbral plant for a maritime climate. The Lower St. John's wort prefers evenly moist but not wet soils that are rather acidic and low in nitrogen. It prefers forest clearings with soils poor in lime. In Central Europe it is a character species of the Isoeto-Nanojuncetea class, but also occurs in societies of the Plantaginetea or Sedo-Scleranthetea class. In the Allgäu Alps in Bavaria, it rises at the Weiherkopf near Bolsterlang to an altitude of 1650 meters.

literature

  • Eckehart J. Jäger, Klaus Werner (Ed.): Excursion flora from Germany . Founded by Werner Rothmaler. 10th edited edition. tape 4 : Vascular Plants: Critical Volume . Elsevier, Spektrum Akademischer Verlag, Munich / Heidelberg 2005, ISBN 3-8274-1496-2 .
  • Henning Haeupler, Thomas Muer: picture atlas of the fern and flowering plants of Germany . Ed .: Federal Agency for Nature Conservation (=  The fern and flowering plants of Germany . Volume 2 ). Eugen Ulmer, Stuttgart (Hohenheim) 2000, ISBN 3-8001-3364-4 .
  • Ruprecht Düll , Herfried Kutzelnigg : Pocket dictionary of plants in Germany and neighboring countries. The most common Central European species in portrait . 7th, corrected and enlarged edition. Quelle & Meyer, Wiebelsheim 2011, ISBN 978-3-494-01424-1 .

Individual evidence

  1. ↑ Oskar Sebald: Guide through nature. Wild plants of Central Europe . ADAC Verlag, Munich 1989, ISBN 3-87003-352-5 , p. 68 .
  2. ↑ a b Erich Oberdorfer : Plant-sociological excursion flora for Germany and neighboring areas. 8th edition. Verlag Eugen Ulmer, Stuttgart 2001, ISBN 3-8001-3131-5 . Page 663.
  3. ↑ Oskar Sebald: Guide through nature. Wild plants of Central Europe . ADAC Verlag, Munich 1989, ISBN 3-87003-352-5 , p. 68 .
  4. ↑ Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings. Volume 2, IHW, Eching 2004, ISBN 3-930167-61-1 , p. 222.

Web links

Commons : prostrate St. John's wort ( Hypericum humifusum )  - album with pictures, videos and audio files