Getting all ancestor elements

[rmuller]

i have a xml-document like:

<elem name=&quot;1&quot;>
<elem name=&quot;1.1&quot;>
<elem name=&quot;1.1.1&quot;>
...
etc.

Problem: the depth is NOT known.
I want a list with all ancestors of the 'deepest' elem-element.
Something like
ancestor::elem[descendant::elem[position()=last()]]
does not work????

thanks
Ronald