We spotted this bitternut hickory, bedecked in wart-like baubles, in Foley Park in Norwich, Vermont. What are all these bumps on the tree’s trunk and branches?
Answer
These are phomopsis galls. As explained in this post by University of Maine Cooperative Extension, these galls “appear to start forming on twigs and small branches before infection of larger branches or the main stem,” and they range “from pea size up to the size of a basketball.”
This week’s contest winner was Leah Williamson