Phomopsis

Phomopsis Gall on Hickory. 

An arboretum walk, a mature tree flowering and leafing out, a lovely spring day, a – gall. A bunch of galls, in fact, on this one tree. At first glance, the galls looked like horned-oak or gouty oak galls, round to oblong stem galls that occur on oak. The areas on the stems even looked sort of oak-ish at first, with masses of pollen-bearing male catkins evident. Not an oak, though, as the compound leaves attested. It was a hickory, and the galls, unlike the insect-induced horned oak and gouty oak galls, were caused by a fungus, the Phomopsis  ...