Sand birch ( Betula pendula ), illustration
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 .
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
Systematics and distribution
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.
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.
Male catkins of a green alder ( Alnus viridis )
Male catkins of a paper birch ( Betula papyrifera )
Male hornbeam catkins ( Carpinus betulus )
Male flowers kittens commons hazel ( Corylus avellana )
Male catkins of the European hop beech ( Ostrya carpinifolia )
- Description of the Betulaceae family. l. at the AP website. (Sections Description and Systematics)
- The Betulaceae family s. st. and The Corylaceae Family at DELTA by L. Watson & MJ Dallwitz. (Section description)
- John J. Furlow: Betulaceae - same text online as the printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico , Volume 3 - Magnoliidae and Hamamelidae , Oxford University Press, New York and Oxford, 1997. ISBN 0-19-511246-6 (sections description and systematics)
- Pei-chun Li, Alexei K. Skvortsov: Betulaceae , p. 286 - the same text online as the printed work , In: Wu Zheng-yi & 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 (Sections Description and Systematics)
- Betulaceae at Tropicos.org. Missouri Botanical Garden, St. Louis
- JJ Furlow: The genera of Betulaceae in the southeastern United States , In: Journal of the Arnold Arboretum , Volume 71, 1990, pp. 1-67.
- Betulaceae in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
- 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 .
- Entries on Betulaceae in Plants For A Future . Retrieved July 31, 2013.
- ZD Chen, SR Manchester & HY Sun: Phylogeny and evolution of the Betulaceae as inferred from DNA sequences, morphology, and palaeobotany . In: American Journal of Botany , 86, 1999, pp. 1168-1181.