542 



A TEXTBOOK OF THEORETICAL BOTANY 



Leaf trace 



Stele 



Fig. 541. — Botrychiuni lunaria. Transverse section of an 

 old rhizome showing medullated stele. 



Mucilage cavity 

 Secondary xylem 



Leaf trace 



Fui. 542. — Botrychiuni virginianum. Transverse section 

 of rhizome showing secondary thickening. 



