i2 4 STUDIES IN FOSSIL BOTANY 



whorled sporophylls which resemble reduced vegetative 

 leaves. In the sporangia, borne on the lower part of 

 each sporophyll, indications of probable megaspores 

 have been traced. 



Professor Nathorst makes this striking plant the 

 type of a distinct class, the Pseudoborniales, showing 

 affinity with the Sphenophyllales, as well as with 

 Archaeocalamites among the Equisetales. The com- 

 plexity of the leaves suggests a comparison with the 

 compound sporophylls of Cheirostrobus, of which the 

 vegetative organs are still unknown, though the fructi- 

 fication of Pseudobornia does not favour any near 

 affinity. In Pseudobornia we appear to have a new 

 and impressive representative of that ancient synthetic 

 race of plants of which the Sphenophyllales have, until 

 now, formed the only known examples. 



