786 



oped more extensively about the base of the bast bundle and represents a 

 radiating overgrowth (k"). The increase in cell numbers begins at once in 

 the layers of the cambial zone (c) lying next to the cut surface, and of the 

 bounding, inner bark which, at the time the pruning was done, lay close to 

 the wood body (a h). 



Exactly as in the protuberance of the roll in the scar wound shown in 

 Fig. 173, the protruding bark zone (n r) is formed from the products of the 



Fie;. 179. 



Fig. isi. 



A one year old branch of the sweet cherry cut through in cross-section, the cut 



surface of which has dried baclt. 



Fijr. 179. From without the cut surface of the branch appears somewhat dried back and has a swelling (a) 



below the dried tissue. Fig. 180. The same branch cut throuKh in tlie median line. Fig. 181. Anatomical 



sketch of the region a to s' of Fig. 180. 



cambial zone and the young bark, and this protuberance is closed in the same 

 way by a cork girdle {k' k"'). The wood products of the cambial zone, the 

 maturing of which changes gradually because of the pressure of the newly 

 produced wound bark, are produced at first as parenchyma wood {hp) in 

 which cord-like, short, porous duct cells {g) occur. The further the for- 

 mation of the new wood, produced after injury, is traced back from the cut 



