Ill] 



PSILOPHYTON 



25 



sions of P. princeps 1 (the nearly smooth type) from the Middle 

 Old Red of Cromarty in Scotland, collected by the present author 

 some years ago, appear to show indistinct indications of the 

 emergences comparable to those of Rhynia and Halle's specimens. 



Fig. 7. The proof of the identity of Psilophyton and 

 Rhynia. (a) Enlarged surface view of a petrified axis of 

 Rhynia Gwynne-V aughani showing surface sculpture and 

 several emergences ("the small projections or bulges" of 

 Kidston and Lang) ( x 14). After Kidston and Lang 

 (1917). (b) Enlarged surface view of an impression of 

 Psilophyton princeps showing surface sculpture and two 

 emergences (the "spines" of Halle) ( x 16). After Halle 

 (1916). ' 



It is thus we think clear that all known examples of P. 

 princeps bore scales or spines, and the anatomy of these structures 

 shows clearly that they are morphologically emergences and 

 neither leaves nor branches. In many cases, however, especially 

 near the apex of the shoots, these emergences are so small and 

 1 No. 25 Devonian Plant Coll., Sedgwick Museum, Cambridge. 



