You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information.
<?xml version="1.0"?>
<api>
  <query>
    <pages>
      <page pageid="374625" ns="0" title="Lamium vreemanii" />
      <page pageid="98623" ns="0" title="Porphyrio porphyrio">
        <images>
          <im ns="6" title="File:Commons-logo.svg" />
          <im ns="6" title="File:Porphyro porphyrio.jpg" />
          <im ns="6" title="File:Purple Swamphen I IMG 9278.jpg" />
        </images>
      </page>
      <page pageid="471078" ns="0" title="Cypris reptans" />
      <page pageid="583523" ns="0" title="Warreopsis" />
      <page pageid="488224" ns="0" title="Papilio (Menelaides) polytes kurokawai" />
      <page pageid="416863" ns="0" title="Solanum microdontum" />
      <page pageid="447454" ns="0" title="Devenilia" />
      <page pageid="297525" ns="0" title="Clematis andersonii" />
      <page pageid="90640" ns="0" title="Lecanactis develans" />
      <page pageid="280234" ns="0" title="Zyginellini" />
    </pages>
  </query>
</api>