On our road walk back to the truck we passed the beautiful tree that you see above. Both of us were sure that we should recognize its unusual shape. Note how the branches curl up at each end? (see picture to the left) We knew that was a definitive feature! Then there were the buds. They were large, over 1/2 inch long each, a rich reddish brown, and.... sticky, yes, really sticky!
We walked just a few more yards and encountered a tree covered with these odd growths. Here was mystery number two. We were pretty sure that it was some sort of gall caused by an insect, but this was not one that I had seen before. The tree it was growing on was an oak, in fact a pin oak (which has a distinctive shape of its own). There were so many galls that I took my penknife and cut one branch off to take home to study. 
Here is another example. Most of the galls were all on one tree. The minute we returned to Irene's she pulled out the tree books, and we quickly identified the tree with the sticky buds and turned up branches. Boy did we feel foolish. We should have recognized it for sure. It is a horsechestnut. They have large palmate leaves with 7 leaflets and a beautiful showy flower in the spring. At any other time of the year we would have known what it was!
Not so many years ago identifying the gall would have been tricky. Now, thanks to the internet it was a snap. This is a horned oak gall, created by a stingless wasp, the Callirhytis cornigera (horned oak gall wasp... duh). They can disfigure trees and cause branches to die back. In some areas of the country they are a bigger problem than others. One adult wasp emerges from each horn when they mature!
Finally, here is just a fun picture of the underside of a downed tree. I just liked the star shape of what is left of the roots.
See Letchworth and Gibsonville
6 comments:
Oh, I may have thought that they were fruits instead of gall, created by a stingless wasp.
Hi rainfield- I doubt you would have thought them a fruit if you had seen them in real life. Nevertheless, they look really strange. Nature is certainly fascinating!
The galls look incredibly interesting. I'd be tempted to take one home to study it too. Since I don't know enough about them, I wouldn't dare. I'm still at the don't touch stage.
Hi Ratty- Well, I knew enough to know it was a gall of some kind, not something poisonous. It looked like the wasps were emerged (dried out with broken areas in the surface), but I'm thinking I should put it in a plastic bag for a while to be sure I haven't transported a pest here.
the gall looks like a fruit (guyabano) we have in the philippines only that it hangs from its tree not wrapping the branch like in these pictures, guyabano is one of my favorite fruits that i really miss now :( looking at your picture makes me hungry and water somehow.
betchai- How strange! How large is the fruit? These galls are just 1.5 - 2 inches across. I have never heard of that.
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