Question: At Quincy Bog in Rumney NH (an area I'm very familiar with), I came upon this solitary specimen of what …
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Question
At Quincy Bog in Rumney NH (an area I'm very familiar with), I came upon this solitary specimen of what appears to be Sorbus americana. This individual plant is about 7' tall and stands under a canopy of white pine, but gets a fair amount of sunlight. Is there enough in the attached photos to distinguish it from Rhus glabra? Is there a sure-fire way to distinguish S. americana from R. glabra without a flower?
Answer
Dear gdewolf, this is a species of Sorbus. Some ways you can distinguish the genera vegetatively. Rhus has a milky latex that would exude from a wound, there are no glands on the leaf rachis, and the axillary winter buds are embedded in the leaf stalk base. In Sorbus, the sap is watery, there are clusters of small, dark glands on the leaf rachis where the leaflets are produced, and the axillary winter buds are observable at the base of the leaf stalk. I hope this is helpful.
