page_title: Alnus alnobetula
section_title: Description
hierarchical_section_title: Alnus alnobetula / Description
caption_attribution_description: English: Alnus viridis ssp. crispa, spruce-fir forest, at edge of parking lot for Roan High Knob trial. Roan Mountain, Mitchell County, North Carolina.
context_page_description: Alnus alnobetula is a common tree widespread across much of Europe, Asia, and North America. Many sources refer to it as Alnus viridis, the green alder, but botanically this is considered an illegitimate name synonymous with Alnus alnobetula subsp. fruticosa.
context_section_description: It is a large shrub or small tree 3–12 m tall with smooth grey bark even in old age. The leaves are shiny green with light green undersurfaces, ovoid, 3–8 cm long and 2–6 cm broad. The flowers are catkins, appearing late in spring after the leaves emerge (unlike other alders which flower before leafing out); the male catkins are pendulous, 4–8 cm long, the female catkins 1 cm long and 0.7 cm broad when mature in late autumn, in clusters of 3–10 on a branched stem. The seeds are small, 1–2 mm long, light brown with a narrow encircling wing.
  The roots of Alnus viridis subsp. sinuata have nitrogen fixing nodules. A study in Alaska showed that Sitka alder seedlings
  were able to invade coal mine spoils and can be used for revegetation and stripmine reclamation.
caption: Foliage and inflorescence, subsp. crispa
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