Betulaceae

Silver birch (Betula pendula ), illustration

The Birch family ( Betulaceae ) are a family in the order of the book -like ( fagales ) within the angiosperms ( Magnoliopsida ). The species of this family are found in the temperate zones of the northern hemisphere and in the mountainous regions of the tropics.

  • 5.1 Notes and references
  • 5.2 Literature

Description

Appearance and leaves

The types of birch plants are deciduous, woody plants and grow as trees or shrubs. The alternate and spiral, two or three rows arranged on the branches, stalked leaves have a simple leaf blade. The leaf margins are (mostly double) sawed, serrated to rarely almost smooth. The stipules usually fall off early.

Inflorescences and flowers

Common to all types of Betulaceae that they are monoecious getrenntgeschlechtig ( monoecious ). On one plant so both male and female inflorescences occur - in this family they are called kittens. In the inflorescences always sit many, very simply constructed flowers, each with only stamens or only with ovary and scars. The male inflorescences are hanging catkins. The female inflorescences are constructed differently depending on the species. The female inflorescences of Coryloideae have foliage leaf-like bracts ( bracts ), on the other hand have the Betuloideae woody inflorescence. In the female flower two carpels are fused to an under standing, two-chambered ovary and there are two free pen available. In each ovary chamber hanging from almost the top of two, or rarely only one ovule. As with many wind-pollinated taxa, the individual flower parts are reduced.

Fruit and seeds

You have wingless nuts or small, winged nut fruits with only one seed. The seeds contain a straight embryo with two flat or thickened cotyledons ( cotyledons ) and no endosperm.

Systematics and distribution

The Betulaceae family was established in 1822 by Asa Gray in A Natural Arrangement of British Plants, 2, 222, 243. Type genus Betula L. is.

The Betulaceae family today includes two subfamilies with six genera and a total of about 110 to 200 species, mainly distributed in the northern hemisphere. In China alone, 89 species are endemic, of which only 56 are on there. The types of hazelnut plants that had previously been considered a separate family Corylaceae are assigned today as subfamily Coryloideae the Betulaceae.

  • Birch family in the narrower sense ( Betuloideae Gray ): The female inflorescences are woody. It contains two species, and about 60 to 100 species: Alder ( Alnus Mill ): The approximately 25 to 40 species are widespread in the New World and Eurasia.
  • Birch (Betula L. ): The approximately 35 to 60 species are widespread in the northern hemisphere.
  • Hornbeam (Carpinus L.): The approximately 25 to 50 species are widespread in Eurasia.
  • Hazelnuts (Corylus L. ): The approximately 15 to 20 species are widespread in the northern hemisphere.
  • Hop hornbeam ( Ostrya Scopoli ): The five to eight species are widespread in the temperate regions of the Northern Hemisphere.
  • Ostryopsis Decne. , The only two to three species are native to China.

Use

Many types of many plant parts are used in very many ways, below just a few examples.

Many Corylus species, the nut fruits are eaten raw or cooked. From the seeds of some species Corylus oil is extracted for use in the kitchen.

Especially from Betula species the bark is very extensively used and processed.

The wood of some species is used.

In some species, the medical effects have been investigated.

Many species and their varieties are used as ornamental plants in parks and gardens.

Pictures

Male catkins:

Male catkins of a paper birch (Betula papyrifera ).

Male catkins of hornbeam (Carpinus betulus ).

Male catkins of Commons, hazel (Corylus avellana ).

Male catkins of the European hop hornbeam ( Ostrya carpinifolia ).

Swell

  • Description of the family Betulaceae S. L. in APWebsite. (Section Description and systematics)
  • The Betulaceae family s.str. The family and the Corylaceae at DELTA by L. Watson & MJ Dallwitz. ( Description section )
  • John J. Furlow: Betulaceae - text the same online as printed work, In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico, Volume 3 - Magnoliidae and Hamamelidae, Oxford University Press, New York and Oxford, in 1997. ISBN 0-19-511246-6 (Section Description and systematics)
  • Pei -chun Li & K. Alexei Skvortsov: Betulaceae, pp. 286 - text the same online as printed work, In: Wu Zheng -yi and Peter H. Raven (eds.): Flora of China, Volume 4 - Cycadaceae through Fagaceae, Science Press and Missouri Botanical Garden Press, Beijing and St. Louis, 1999. ISBN 0-915279-70-3 (Section Description and systematics)
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