ACROGENS. 



55 



arranged with great regularity. The stem shows some 

 indication of the separation of a bark-like portion 

 from the pith-like, by the intervention of a circle of 

 bundles of elongated cells, from which branches pass 

 into the leaves, so as to afford them a sort of midrib. 



The root-fibers are long, tubular cells, quite trans- 

 parent, within which the circulation of bioplasm may 



be seen. 



