Birch
From Wikipedia, the free encyclopedia.

Betula
A birch tree
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Fagales Family: Betulaceae Genus: Betula
Species
Many species, see text. Also: Classification

Birch is the name of any tree of the genus Betula, in the family Betulaceae, closely related to the beech/oak family, Fagaceae. These are generally small to medium-size trees or shrubs, mostly of northern temperate climates. The simple leaves may be toothed or lobed. The fruit is a small samara, although the wings may be obscure in some species. They differ from the alders (Alnus, the other genus in the family) in that the female catkins are not woody and disintegrate at maturity, falling apart to release the seeds, unlike the woody cone-like female alder catkins.

In times past, commercial oil of wintergreen (methyl salicylate) was made from the sweet birch Betula lenta.

Birches of North America include:

• Betula allegheniensis - Yellow birch (B. lutea)
• Betula cordifolia - Mountain paper birch
• Betula glandulosa - American dwarf birch
• Betula lenta - Sweet birch or Cherry birch
  • Betula lenta subsp. uber - Cherry Creek birch (endemic, Cherry Creek, Smythe Co., VA)
• Betula michauxii - Newfoundland dwarf birch
• Betula neoalaskana - Alaska birch or Yukon birch
• Betula nigra - River birch or Black birch
• Betula occidentalis - Water birch or Red birch (B. fontinalis)
• Betula papyrifera - Paper birch, Canoe birch or White birch
• Betula populifolia - Gray birch
• Betula pumila - Swamp birch

European & SW Asian birches include:

• Betula medwediewii - Caucasian birch
• Betula nana - Dwarf birch (also in Asia)
• Betula pendula - Silver birch
• Betula pubescens - White birch, European white birch or Downy birch (also in northern Asia)
  • Betula pubescens subsp. tortuosa - Arctic white birch (subarctic Eurasia, Greenland)
    • Many American texts appear to have B. pendula and B. pubescens confused, though they are distinct species with different chromosome numbers

Asian birches include:

• Betula albosinensis - Chinese red birch
  • Betula albosinensis var. septentrionalis - [[North Chinese red birch
• Betula alnoides - Alder-leaf birch
• Betula austrosinensis - South China birch
• Betula chinensis - Chinese dwarf birch
• Betula ermanii - Erman's birch
• Betula grossa - Japanese cherry birch
• B. jacquemontii (Betula utilis subsp. jacquemontii) - White-barked Himalayan birch
• Betula mandschurica - Manchurian birch
  • Betula mandschurica var. japonica - Japanese birch
• Betula maximowiczii - Monarch birch
• Betula platyphylla (Betula pendula var. platyphylla) - Siberian silver birch
• Betula szechuanica (Betula pendula var. szechuanica) - Sichuan birch
• Betula utilis - Himalayan birch

Classification

See also: Trees of Britain, Trees of the world, Birching

The original article can be found at: http://en.wikipedia.org/wiki/Birch.
All text is available under the terms of the GNU Free Documentation License.