STRUCTURE OF THE ROOT 



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Fig. 63. 

 a, b, Successiveh' older sections of the root of the Bean {Vicia Faba), showing the 

 beginning of cambial acti\'ity. In [a) divisions appear {cb) in the coniuncti\'e 

 parench^'ma internally to the phloem, but the pericycle {per) is quiescent. In [b] the 

 cambium has already fonned xylem internally {2nd a-y),and phloem externally 

 {2nd phi), and cell division has spread to the pericycle, and is continnons outside the 

 protoxylem {pr.xy). { -■■ 100.) 



appear, as in the stem. Consequently an old root of a Dicotyledon 

 acquires a structure very like that of an old stem (Fig. 64). The 

 difference may be often observed even in old roots by looking for the 



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