Red-Pea Galls on Quercus pyrenaica Oaks

This is a collection of images of Red Pea Galls taken from one Quercus pyrenaica tree (In English this tree is called the Pyrenean Oak although in fact this species is not hardly found at all in the Pyrenees mountains but rather in central and southern Spain. All these images were taken on the same day and depict the galls in their stage of formation. Another name for these is Red Currant Galls. In a previous post I have blogged about the "Apple Galls" associated with the Pyrenean Oak as well.

I found these pea sized galls on a tree in the Spanish region of Extremadura in the province of Cacares near the small town of Logrosan. I was a bit puzzled at first because the galls did not look anything like the apple galls or the marble galls that I am familiar with. I knew that some galls formed on the reverse side of some Oak leaves but on these trees there were numerous galls on the tree flower. The image below is of a cluster of these galls that formed on a flower and continued to form even after the flower had released most of its polen.

Suspecting that they were galls I cut one of the larger ones open and found the larvae of what I believe is the Cynips divisa wasp inside. See image below. I also collected a few and placed them in a jar to see if I can get a look at what the wasp looks like when it emerges from the gall.

The images below are of these same galls when they form on the undersides of the leaves.


  1. We saw one on the underside of an Oak leaf. Thanks for the pictures on the web site, we used them to figure out that we had a red pea gall.

  2. My oak tree is covered with these galls this year causing the leaves to be stunted and to shrivel, the tree has not been healthy for about 3 years suffering from early leaf die back causing new leaves to grow mid summer.
    Having asked advice from my local garden centre it must be well watered and fed in autumn, I hope that cures it