GPath: descendant-or-self ?

Hi

I like the Groovy simple syntax to query XML, but I can't find how to do the equivalent 
of descendant-or-self XPath expression. For instance, how can I print the names of all 
elements which tag is "X", when this tag can be used at any level of the XML 
tree ?

For these two files:

1.xml:

<X name="one">
  <Y>
     <X name="two"/>
  </Y>
</X>

2.xml:

<Y>
  <Y>
     <X name="one">
       <X name="two"/>
     </X>
  </Y>
</Y>   

I want to have the following output:
one
two

In XPath, I would simply do "//X/@name"

Thanks for your help