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Betulaceae Birch Family
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The birch family, the Betulaceae, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeams, and hop-hornbeams. • Alder: • Alder - Alnus glutinosa • Birch: • Betula pendula - silver birch • Hazel: • Hazel - Corylus • Hornbeam: • Hornbeam - Carpinus • The Betulaceae are believed to have originated at the end of the Cretaceous period (about 70 million years ago) in central China when the region had a Mediterranean climate due to the proximity of the Tethys Sea. All six genera and 52 species are native to this region, many of those being endemic. All six modern genera are believed to have diverged fully by the Oligocene, with all genera in the family (with the exception of Ostryopsis) having a fossil record stretching back at least 20 million years from the present. • In the family Betulaceae, notably in the genera Carpinus and Corylus, the involucre is a leafy structure (specialized leafy whorl) that protects the developing nuts. • In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. • ALDER [ 0:04 ] is the common name of a genus of flowering plants (Alnus) belonging to the birch family Betulaceae. The genus (~30 species) comprises monoecious trees and shrubs, a few reaching a large size. Members are distributed throughout the north temperate zone. • Monoecious refers to plants with unisexual flowers on the same individual, and plants with bisexual flowers. Individuals bearing separate flowers of both sexes at the same time are called simultaneously or synchronously monoecious Individuals that bear flowers of one sex at one time are called consecutively monoecious. • BIRCH [ 0:23 ] is a broadleaved deciduous hardwood tree of the genus Betula. They are typically rather short-lived pioneer species widespread in the Northern Hemisphere, particularly in northern temperate and boreal climates. This tree is sometimes called The Watchful Tree because of eye-like impressions on the bark. • The HAZEL (Corylus) [ 0:51 ] is a genus of deciduous trees and large shrubs native to the temperate Northern Hemisphere. The genus is usually placed in the birch family Betulaceae (some botanists split the hazels (with the hornbeams and allied genera) into a separate family Corylaceae). • HORNBEAMS [ 1:24 ] are relatively small hardwood trees in the genus Carpinus. Modern botanists place the hornbeams in the birch subfamily Coryloideae. The 30–40 species occur across much of the north temperate regions, with the greatest number of species in east Asia, particularly China. Only two species occur in Europe, only one in eastern North America, and one in Mesoamerica. • Ostrya [ 1:11 ] is a genus of eight to 10 small deciduous trees belonging to the birch family Betulaceae. The common name is hophornbeam in American English and HOP-HORNBEAM in British English. It may also be called ironwood, a name shared with a number of other plants. • The wood is very hard and heavy; the name Ostrya is derived from the Greek word ostrua, bone-like , referring to the very hard wood. • The genus is native in southern Europe, southwest and eastern Asia, and North and Central America. They have a conical or irregular crown and a scaly, rough bark. They have alternate and double-toothed birch-like leaves. The flowers are produced in spring. Male catkins are twice as long as female catkins. Fruit form in pendulous clusters with 6–20 seeds; each seed is a small nut, fully enclosed in a bladder-like involucre. • Ostryopsis [ 2:05 ] is a small genus of deciduous shrubs belonging to the birch family Betulaceae. The species have no common English name, though HAZEL-HORNBEAM has been suggested, reflecting their similarities to the closely related Hazels and Hop-hornbeams. • Alder 0:04 http://en.wikipedia.org/wiki/Alder • Birch 0:23 http://en.wikipedia.org/wiki/Birch • Hazel 0:51 http://en.wikipedia.org/wiki/Hazel • Hop-hornbeam 1:11 https://en.wikipedia.org/wiki/Ostrya • Hornbeam 1:24 http://en.wikipedia.org/wiki/Hornbeam • Hazel-hornbeam 2:05 http://en.wikipedia.org/wiki/Ostryopsis • http://en.wikipedia.org/wiki/Plant_re...
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