THE F1BRO-VASCULAR SYSTEM. 



109 



this by one of sieTe tissue ; this again by fibrous tissue, and 

 so on. 



137. A similar but not identical structure is found in the 



Pig. 98. Part of the cross-section of an old root of Adlantum Morilzianum. 



pa- 

 on 



. . . 



hairs of the root surface; M,M, bundle sheath (endodermis) ; between A and M, 

 renchyma ; pc, pericambiuin ; pr, a plate of tracheary tissue, which is bounded 

 each side by sieve tissue. X 225. After De Bary. 



bundle of the rhizome of Polypodium vulgar e. Here the 

 central portion of the stem is made up of scalariform tissue 

 (Fig. 97, the larger, thicker-walled tissue), and this is sur- 

 rounded by a tissue which may be regarded as but partly 



