Oak Gall, induced by a Cynipid Wasp
Northern Sierra Nevada, California, USA

photograph © Alex Wild 2004

This bizarre growth on a leaf of Quercus vacciniifolia is induced by the larva of a small wasp in the family Cynipidae, which lives inside feeding on plant tissue. 

USA, CA, Nevada Co.: Sagehen Creek Field Station. 23.vii.2004, 39º26'N 120º14'W, 1920m
Open Jeffrey Pine forest, ex Quercus vacciniifolia.

This image is copyrighted by the photographer and cannot be used without permission. To obtain permission to use this image, please email Alex Wild. (alwild (at)  Most of the photographs on are reduced from their original size and compressed for more efficient web transmission.  In some cases, higher quality versions are available.

This image was captured with a Canon EOS D60, with a Canon 65/2.8 MPE 1-5x Macro lens.