Gall on Thistle

Gall on Thistle

Observation - Gall on Thistle - UK and Ireland. Description: Large swelling in on the stem of a thistle. I know nothing about identifying galls. I have put this under plants as I am not sure if this is an gall caused by invertebrates or fungus.

Large swelling in on the stem of a thistle. I know nothing about identifying galls. I have put this under plants as I am not sure if this is an gall caused by invertebrates or fungus.