Cherry Galls

24 December 2013

Coxley Valley, mixed woodland at top of slope upstream from the quarry.

These 1 to 2 centimetre galls on the leaf of sessile oak, Quercus petraea, are cherry galls of the gall wasp Cynips quercus-folii feed and pupate. One larva develops, then pupates, in the centre of each gall.

The adult wasps emerge from December to February and lay parthenogenic eggs on buds which develop into violet-egg galls.

The generation which emerges from the violet-egg galls in spring includes both males and females. The females of this summer generation lay their eggs in the phloem* tissue of leaf veins and these develop into cherry galls.

* Phloem carries the sugars produced by photosynthesis down from the leaves.

Plant Galls in Colour

I identified these galls using Arnold Darlington's The Pocket Encyclopaedia of Plant Galls in Colour, Blandford Press, 1968. I'd always coveted this little classic and used to borrow it occasionally from the small branch library where Barbara used to work.

'If this book is ever weeded from the shelves and put in the book sale for 10 pence make sure you let me know!' I insisted.

Sure enough it was weeded out and it's now on my shelf, rubbing shoulders with the tail end of my plant section on one side and the start of my animal life section on the other.

It still has its library card and the original loans slip. Frequently on loan from Wakefield's central library between the summers of 1968 and 1971 it migrated to Flanshaw library in the autumn of 1971 where it was last stamped out, probably to me, in June 1999.

Dewey class; J580.