Distribution of genus <i>Obregonia</i>
<a href="//commons.wikimedia.org/wiki/User:Succu" title="User:Succu">Succu</a>
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<span class="int-own-work" lang="en">Own work</span> based on <a href="//commons.wikimedia.org/wiki/File:Mexico_States_blank_map.svg" title="File:Mexico States blank map.svg">File:Mexico States blank map.svg</a> and Ulises Guzmán: <i>Catálogo de cactáceas mexicanas</i>. 2003, p. 173