Alder Tongue

Alder Tongue first appeared in Britain in the 1940s but has spread rapidly. I don't recall seeing it in the lower Ouse Valley before but I thought I would have a look for it this morning when walking the spaniel. I found it on the fifth tree I looked at and then on another three within ten minutes. The fungus  Taphrina amentorum causes the tree to produce these weird shaped galls from the new cones.