Fig. 33. Some Ancestral Forms of Buttonball Leaves (About f 

 Natural Size) 



1, 2. Leaves of adventitive twigs from old stumps of the existing Platanus 

 occidentalis Linn. 



3. A leaf of a seedling of the species. 



4. Platanus shirleyensis Berry, an Upper Cretaceous Platanus from Alabama. 



5. A non-lobate leaf of Platanus Kummeli Berry from the Upper Cretaceous 

 of New Jersey. 



161 



