Shrub birch
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Shrub birch ( Betula humilis ) |
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The shrub birch ( Betula humilis ), also called the low birch , is a species of birch ( Betula ). It predominantly thrives in bog forests in Eurasia .
description
Vegetative characteristics
The shrub birch is a low, richly branched shrub that reaches heights of 0.5 to 3 meters. The brown bark of young twigs is initially hairy and covered with many resin glands.
The leaves are 1 to 4 cm long, 0.5 to 2.5 cm wide, rounded to ovoid, longer than wide and often slightly asymmetrical. They are blunt or slightly pointed, coarse and unequal and single to double sawed. They have four to six pairs of silk veins on each side, are light green on each side and have hair on the underside in the corners of the nerves or are bald. The petiole is 2 to 5 mm long.
Generative characteristics
The flowering period extends from April to May. The kittens are all erect. The male kittens are usually a bit slimmer than the female.
The short-stalked catkins are oval to cylindrical with a length of 10 to 15 millimeters and a diameter of 5 to 8 millimeters. The side lobes of the fruit scales are almost as long as the middle lobes and stick out only a little. The fruit wings are much narrower than the single-seeded nut fruit.
The number of chromosomes is 2n = 28 or 56.
Occurrence and endangerment
The main distribution of the shrub birch is in continental Eurasia . Its westernmost occurrence is in Germany. In Germany it is endangered and can only be found in the Alpine foothills and in a few places in the North German Plain . In Switzerland there was a single copy in the canton of St. Gallen in 2019.
The shrub birch grows on bog meadows, in alder quarries and in flat and raised bogs . It thrives on wet, moderately nutrient-rich, base-rich, moderately acidic, musty peat soils. It is a species of the Betulo-Salicetum repentis from the association Salicion cinereae .
The bush birch is an ice age relic in Central Europe . It is believed that the decline is due to a natural process of extinction accelerated by the destruction of the shrub birch habitat. As a maintenance measure, the plants should be protected from being bitten by game, thereby enabling fruiting.
literature
- Erich Oberdorfer : Plant-sociological excursion flora . With the collaboration of Theo Müller. 7th, revised and expanded edition. Eugen Ulmer, Stuttgart (Hohenheim) 1994, ISBN 3-8252-1828-7 .
- Gunter Steinbach (Ed.): Shrub trees (Steinbach's natural guide). Mosaik Verlag GmbH, Munich 1996, ISBN 3-576-10560-3 .
Individual evidence
- ↑ 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 314.
- ↑ The rarest tree in Switzerland is in the canton of St. Gallen , NZZ, July 10, 2019
- ↑ Erhard Dörr, Wolfgang Lippert : Flora of the Allgäu and its surroundings. Volume 1, IHW, Eching 2001, ISBN 3-930167-50-6 , p. 421.
Web links
- Shrub birch. In: FloraWeb.de.
- Shrub birch . In: BiolFlor, the database of biological-ecological characteristics of the flora of Germany.
- Betula humilis closet In: Info Flora , the national data and information center for Swiss flora . Retrieved October 3, 2015.
- Profile and distribution map for Bavaria . In: Botanical Information Hub of Bavaria .
- Thomas Meyer: Data sheet with identification key and photos at Flora-de: Flora von Deutschland (old name of the website: Flowers in Swabia )
- Photos from the Natural History Museum Vienna.