The green alga <i>Halimeda</i>, after illustration attributed to J.M. Martin <i>et al</i>.
<a href="//commons.wikimedia.org/wiki/User:Verisimilus" class="mw-redirect" title="User:Verisimilus">Verisimilus</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>