Hi Joyce . I am not sure if the park is named . Take Louise turnoff from freeway ... go down about 3 miles over 3 railroad tracks ( just after 3rd track ) then make a left turn on Marguerite which turns into Nicol ... go straight about a half mile and on the left is the grassy park . The Oak tree with the Galls is the first one ( right after a small dead tree ) in line just after the childrens playground along the cement wall/fence . Also , on the other end of the park there is another tree with many of the same fuzzy galls on the leaves ... it is closest to the wall from the sidewalk ( across from fenced off utility ) . Hope these are good enough directions , Beth

Hi Beth -- I went to the field on Monday. Very good timing because I was on my way to meet up with some cynipid gall researchers, including three from Europe who have been traveling in the U.S. to find cynipid galls. I showed them photos, leaves, acorns, and galls. We decided that the oak is Quercus virginiana which is native to the southeast. We all agreed that the galls (and their wasps) are not native to California either. Probably when the trees were brought to California they came with some eggs or wasp larvae already on them, and they developed and have been doing well ever since. They probably have no parasites here, and they probably can't live on any of our native oaks, so they will have a very limited distribution in Primavera Park as long as those trees are there. I found no galls native to CA on the trees. But like you have shown us, these trees are sure covered with the galls that they do have!

It's not that common to find non-native oaks with galls from wasps that normally only occur where the trees are native. So this is an interesting find.

As to which species of cynipid these are, no one knew off-hand. I'll spend a little time looking at what few (old, incomplete, and out-of-date) book resources there are -- haven't had time yet. So far it seems that there is more than one possibility for what species this is. More on this later. Thanks for posting these interesting photos.