536 



A TEXTBOOK OF THEORETICAL BOTANY 



Fig. 533. — Marattia fraxinea. Dissected stele isolated from 

 soft tissues. The black areas represent meristeles cut in 

 transverse section. Several paired leaf traces may be 

 seen arising around the periphery. (After West.) 



Anatomy of the Root 



The root of Marattia differs greatly from that generally found in the 

 Leptosporangiatae. It has a broad, soft cortex and a stele which contains 

 about a dozen xylem strands, with external protoxylems, alternating with 

 phloem groups (Fig. 534). As in the stem, there is no endodermis. The 

 arrangement of the vascular tissue recalls that in a monocotyledonous root. 



T 



A If A r-- ■\. ,^ fr--^ .1 t 



•r-' 



* 





■'H 







'-^ ■<iK 



- •• • >6h • ^\j. ■•■■ 





A 



} 



Fig. 534. — Marattia fraxinea. Transverse section 

 of root showing polyarch structure. 



