I have used sycamore leaves with wonderful results.  BTW, you ought to check out the toilet tissue tablets that you can get on Amazon.  I just got some.  They are nifty wipes for backpackers.  
Fourteen sturdy wipes will fit into one of those little tubes that hikers often use for keeping a small emergency supply of matches dry.  The bottom line, as they say, is that fourteen wipes occupy practically no space at all.
Thanks, but I don't carry buttwipe... Well, I DO, but not much, so I don't use it much... wet weather and emergencies...
 I just use grass or cedar bark or some such... if you know how to make a birds nest for lighting a fire, you don't need TP. Just miff the stuff till it's soft and downy, even more than you would for a fire,  and away you go... Then I ain't got to worry about counting squares to make sure I have enough to last.