Galls on Oak Tree

True Marta!!

I was looking in the wrong places for this plant. Since I found it in Walnut Creek , I thought it was possibly a Walnut tree. Also searched in Macadamia nuts ,hickory etc. Turns out that it is " Galls " on oak tree and is formed by wasps and aids in the life cycle of those insects like wasp. The larva secretes a chemical which interacts with the plant tissue. it then forms a gall and as a result is enclosed in the Gall. Now it is in a safe home and it feeds on the gall! Galls are usually harmless ,depending on the location . Home owners like to get rid of them ,because of the way they look. Early settlers used galls to make ink/ http://ento.psu.edu/extension/factsheets/galls-oak You can find more info in the above link. The librarian at the Walnut Creek Library helped me in the identification.

pyoung ,the leaves are very distinct and they do not look like the leaves of a Walnut or Macadamia nut Tree.

I am trying to figure out what it is . It is from the city of Walnut Creek,which is named so because of the abundance of Walnut trees.