Acorn of Cork oak <a href="//commons.wikimedia.org/wiki/Quercus_suber" title="Quercus suber">Quercus suber</a>, Ceuta, Spain.
<a href="//commons.wikimedia.org/wiki/User:Xemenendura" title="User:Xemenendura">Xemenendura</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>