Cola-nut galls (Andricus lignicola) cut open to see the internal chamber.
<a href="//commons.wikimedia.org/wiki/User:Rosser1954" title="User:Rosser1954">Rosser1954</a> Roger Griffith
3 November 2008, 15:28:43 (according to <a href="https://en.wikipedia.org/wiki/Exchangeable_image_file_format" class="extiw" title="en:Exchangeable image file format">Exif</a> data)
<span class="int-own-work" lang="en">Own work</span>