204 



THE ANATOMY OF WOODY PLANTS 



an important and phylogenetically interesting component of the 

 foliar fibrovascular strands in many gymnosperms. They are not 

 a salient, and certainly not a primitive, feature of organization of 



FIG. 151. Transverse section of the leaf bundle in Cordaiies principalis 



the leaf bundles of the living Cycadales and their allies, the Paleozoic 

 Medulloseae. The transfusion sheath of the foliar bundles in the 

 Cordaitales did not always manifest the complexity that it shows 

 in the case of C. principalis figured above. In most instances only 

 the broader and shorter thin-walled elements were present, the 



