Birch plants


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Birch plants
Sand birch (Betula pendula), illustration

Sand birch ( Betula pendula ), illustration

Systematics
Eudicotyledons
Nuclear eudicotyledons
Rosids
Eurosiden I
Order : Beech-like (Fagales)
Family : Birch plants
Scientific name
Betulaceae
Gray

The birch family (Betulaceae) are a family of plants in the order of the beech-like (Fagales) within the flowering plants (Magnoliopsida). The 110 to 200 species are distributed in the temperate areas of the northern hemisphere and in the mountainous regions of the tropics .

description

Appearance and leaves

The species of the birch family 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) serrated, serrated or rarely almost smooth. The stipules usually fall off early.

Inflorescences and flowers

What all species of the Betulaceae have in common is that they are single-sexed ( monoecious ). So on one plant specimen there are female and male inflorescences - in this family they are called catkins. In the inflorescences there are always many, very simply built flowers , each with only stamens or only with ovaries and stigmas. The male inflorescences are pendulous catkins . The female inflorescences are structured differently depending on the genus . The female inflorescences of Coryloideae have foliage leaf-like bracts (bracts), however, have the Betuloideae woody inflorescences. In the female flowers are two carpels fused into one under permanent, two-chambered ovary and there are two free pen available. In each ovary chamber hang from almost the tip of two, or rarely only one, ovules . As with many wind-pollinated taxa , the individual flower parts are reduced.

Fruits and seeds

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

Systematics and distribution

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

The Betulaceae family today contains two subfamilies with six genera and a total of 110 to 200 species, which are mainly found in the northern hemisphere . There are 89 species native to China alone, 56 of which are found only there. The species of the hazelnut family, which were previously regarded as a separate family Corylaceae, are now assigned to the Betulaceae as the subfamily Coryloideae .

  • Birch family in the narrower sense (Betuloideae Gray ): The female inflorescences are woody. It contains two genera and 60 to 100 species:
  • Hazelnut family (Coryloideae Koehne ): Here the female inflorescences have bracts similar to foliage. It contains four genera with 50 to 80 species:
    • Hornbeams ( Carpinus L. ): The 25 to 50 species are common in Eurasia.
    • Hazelnuts ( Corylus L. ): The 15 to 20 species are common in the northern hemisphere.
    • Hop beech ( Ostrya Scopoli ): The five to eight species are widespread in the temperate areas of the northern hemisphere.
    • False hop beech ( Ostryopsis Decne. ): There are three species that are native to China since 2010.

use

Many plant parts are used in a wide variety of ways by many species, here are just a few examples.

The nuts of many Corylus species are eaten raw or cooked. The seeds of some species of Corylus are used to make oil for use in cooking.

The bark of Betula species in particular is used and processed in a variety of ways.

The wood of some species is used.

The medicinal effects of some species have been studied.

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

photos

Male catkins:

swell

Individual evidence

  1. Betulaceae at Tropicos.org. Missouri Botanical Garden, St. Louis
  2. ^ JJ Furlow: The genera of Betulaceae in the southeastern United States , In: Journal of the Arnold Arboretum , Volume 71, 1990, pp. 1-67.
  3. Betulaceae in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  4. Walter Erhardt , Erich Götz, Nils Bödeker, Siegmund Seybold: The great zander. Encyclopedia of Plant Names. Volume 2. Types and varieties. Eugen Ulmer, Stuttgart (Hohenheim) 2008, ISBN 978-3-8001-5406-7 .
  5. a b c d Entries on Betulaceae in Plants For A Future . Retrieved July 31, 2013.

literature

Web links

Commons : Birch Family (Betulaceae)  - Collection of images, videos and audio files