350 



MANUAL OF BOTANY 



of bast. This is seen in most Ferns {fig. 733). Sotaetimes an 

 apparently concentric bundle is formed by the fusion of a number 

 of wood bundles to form a single mass, which is surromided 

 by a ring of bast, itself the result of a fusion of separate 

 bundles. Such a bundle is termed gamodcsniic : it may be 



Via. 736. 



Fhj. 736. Section of stele of root. After Kny. tin, Budodermis. pe. Peri- 

 cycle. X. Xylem bundles, the protoxyiem, x^, abutting on tlie pericycle. 

 pfi. Phloem bundles alternating with the bundles of xylem. p. Pith, or 

 conjunctive titsue of the stele. 



seen in many Selaginellas and Ferns (fig. 734). It is better 

 regarded as a stele. 



In the other variety we find the bast central, and the wood 

 surrounding it. , It occurs in a few Monocotyledons (fig. 735). 

 Concentric bvmdles never contain any cambium. 



The wood and bast bundles of the stele of the root are not 

 conjoint but separate. They are said to be radially arranged as 



