Mountain-ash Sorbus americana and S. decora
Family: Rosaceae (Rose)
These small northern trees are not actually Ashes, but members of the
Rose family. There are two native species: American (S. americana) and Showy (S. decora), though they don't seem to be easily separated, especially in the winter. One introduced species, European (S. aucuparia),
is commonly planted in cities, and is the most likely to be found in
southern Ontario. All three closely resemble each other in size
and form, especially the two native species. The main differences
are in the buds, which are hairy for European Mountain-ash and shiny
and resinous for the native species. The buds are
fairly large, especially the end bud, and are typically reddish in
colour. The bark is usually marked with horizontal slits similar
cherries and birches, though it's not too evident on these pictures..
I'm not sure if any winter characteristics are consistent enough
to allow seperation between the two native species...
Winter twig and end bud of a native Mountain-ash
Another view of the end bud and leaf scars
End bud and leaf scars. Often the leaf scars are crowded together on "spur branches"
Another view of the spur branches with an end bud
Another view of the winter twig.
Slightly older bark
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© 2008 Josh Sayers
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