Sunday, May 23, 2010

Well, gall-eeee!!

One thing we have plenty of here in the Not-So-Big Woods is leaves, and when you've got leaves, you've got galls.

Awesome Husband refers to galls as "tree warts," and that's what they look like. These leafy protuberances form when an insect, often a wasp or a mite, lays her egg inside a leaf's tissue. The egg, and later, the larva, produce hormones that interact with the plant to form a...well, a sort of wart. The wartiness provides food and shelter for the developing larva. When the larva matures, it chews its way out of its little house, and goes on to make more warts on more trees. Galls are unsightly, but they don't usually hurt the tree.

Since they're generally harmless, we can just enjoy their weirdness.

This gall, attached to an oak leaf, looks like a beetle. Fairly smooth and hard, it's a single, but some leaves are covered in them.

 On the other hand, these elm galls are smaller, softer, and a bit fuzzy. Some of them are pink, making it look like Captain Crunch visited and left some dimunitive Crunch Berries behind. (note to Quaker Oats Legal Dept.: I am not trying to insinuate that your Crunchberries contain larvae).

The pecan leaves are taking the hardest hit, aesthetically speaking. Multiple galls infest each leaf, and they're large ones. They're distorting the leaves, pulling them out of shape.

Different galls on the elm leaves are more cylindrical than most, and also covered in fuzz. They appeared very early in the season, when the leaves were first emerging.

And finally, these tiny little  pointy things, perched on a hackberry leaf, casting shadows like mountains in the setting sun.

Those are just the galls I found in a 15-minute period in a hundred-foot stretch of trees lining the driveway. The variety is breath-taking, and I know there are more waiting in the woods.


  1. I was just noticing the variety of galls in the trees bordering my back yard fence the other day. You're right...there are so many different kinds. It would be cool to watch them closely enough to see what kind of insects eventually emerged.

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  3. Some of our Black Cherry trees, particularly those in the woods, develop galls somewhat like you see on the hackberry leaves. I'm not sure I have the patience to check on them often enough to see what emerges.

  4. these tiny little pointy things, perched on a hackberry leaf, casting shadows like mountains in the setting sun.
    are these things harmful to humans or pets? they look weird. I have them just on one small scrubby tree in my yard.

  5. To my knowledge, the galls aren't harmful to anyone or anything. I wouldn't try to saute them for lunch, because they do contain larvae, but they aren't toxic.