Is there a way to get simple XML child elements by node name?

In PHP, is there an existing method to get one or more child elements by node name (recursively) or would you have to write a function for that yourself?

For example, this is my XML:

<parent>
    <child>
        <grandchild>Jan</grandchild>
        <grandchild>Kees</grandchild>
    </child>
</parent>

And I'm looking for a method that returns something like: Array( [0] => 'Jan', [1] => 'Kees' )

by means of calling something like:

$grandchildren = $xml->children('grandchild');

The above does exist according to documentation but only for namespaces.