Oak Artichoke Gall

We needed to drop a parcel off at the post office.  We followed this up with a walk round the village 
Just at the end of the village is the village pound.  A pound being where in times gone by stray livestock were impounded until ownership was sorted out.

The pound now has bench in it and an oak tree.  I started by taking shots of acorns (pedunculated oak).  Then I spotted these strange things.  An app told me what they were, I had never seen one like that before.

Galls are caused by a tiny wasp.  It lays an egg on a bud that developed into the gall that protects the growing grub.  The grub stays in the gall until it emerges in spring.  Note no mention of mating as the species is parthenogenic i.e. can produce fertile eggs without mating.