XXIIl] 



OAULOPTERIS 



421 



as the most primitive representative of the genus Psaronius so 

 far discovered. 



Psaronius stems freserved as casts showing surface-features, 

 or in a decorticated state. 



i. Caulopteris. 



This generic name was instituted by Lindley and Hutton' 

 for tree-fern stems from the English Coal-Measures showing 

 circular or oval scars arranged quincuncially. The vascular tissue 

 of the petiole is represented by a U-shaped impression on the 



Fio. 298. A. Caulopteris peltigera. 

 B. Mepaphytoii insigne. 

 (After Grand'Eury.) Much reduced. 



scar, the ends of the U being incurved, or by a closed oval ring 

 with a wide-open and inverted V near its upper end. The 

 surface between the leaf-scars bears the impression of adven- 

 titious roots. Caulopteris is represented, in the Upper Coal- 

 Measures of England, by C. anglica^ Kidst. The species 

 C. peltigera (fig. 298, A), originally described by Brongniart as 

 Sigillaria, illustrates the closed form of leaf-trace and, as Zeiller 

 suggests, it is the cast of a Psaronius stem which possessed 

 a vascular system on the same plan as that of P. infarctus. 

 C. Saportae'' illustrates the open U-shaped type of petiole stele. 



1 Lindley and Hutton (3,S) A. PI. xlii. 



3 Eenault and Zeiller (88) A. PI. xxxv. fig. 6. 



2 Kidston (88) PL xxvi. 



