Alder

About 20-30 species, see text.

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Alder is the common name of a genus of flowering plants (Alnus) belonging to the birch family (Family Betulaceae). The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate zone, and in the New World also along the Andes southwards to Chile. The leaves are deciduous (evergreen or nearly so in a few species), alternate, simple, and serrated. The flowers are catkins with elongate male catkins on the same plant as shorter female catkins, often before leaves appear; they are mainly wind-pollinated, but also visited by bees to a small extent. They differ from the birches (Betula, the other genus in the family) in that the female catkins are woody and do not disintegrate at maturity, opening to release the seeds in a similar manner to many conifer cones.

Related Topics:
Genus - Flowering plant - Betulaceae - Species - Monoecious - Tree - Shrub - New World - Andes - Chile - Leaves - Deciduous - Evergreen - Flower - Catkin - Bee - Birch - Conifer cones

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The best-known species is the Common or Black Alder (A. glutinosa), native to most of Europe and widely introduced elsewhere. The largest species is Red Alder (A. rubra), reaching 35 m (the tallest is 32 m) on the west coast of North America, with Black Alder and Italian Alder (A. cordata) both reaching about 30 m. By contrast, the widespread Green Alder (A. viridis) is rarely more than a 5 m shrub.

Related Topics:
Black Alder - Europe - Red Alder - North America - Italian Alder - Green Alder

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The common name alder is derived from an old Germanic root. The botanic name Alnus is the original Latin name.

Related Topics:
Germanic - Latin

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