Edit in JSFiddle

<style type="text/css">
    p:nth-child(2){color:red;}
    p:nth-of-type(2){border:1px solid #000;}
</style>
<div id="test">
    <p>P One</p>
    <p>P Two</p>
</div>
<div id="test">
    <span>Span Test</span>
    <p>P One</p>
    <p>P Two</p>
</div>