PSARONIUS 299 



development. The question, however, deserves further 

 investigation. 



In the central region of the stem we see at once 

 that the vascular system is remarkably complex, con- 

 sisting of a great number of regularly disposed steles, 



Fig. 113. — Psaj-ouiits brasiliensis. Transverse section of stem. The whole of the central 

 portion, containing the vascular bundles, is shown, together with a great part of the 

 cortex, traversed by innumerable adventitious roots. Fi, F2, leaf -gaps. For detailed 

 description, see text. The round objects at o are accidental perforations. Reduced. 

 After Zeiller. 



usually much elongated in transverse section, but 

 varying greatly in size and form. At two opposite 

 points (Fig. 113, Fi and F2) outgoing leaf-traces are 

 shown. The leaves appear to have been decussately 

 arranged, but those of the same pair were not precisely 

 at the same level. At F2 the open curve of the out- 



