^6o 



and is cut off by a cork layer w itliin the boundaries of the living tissue. In 

 the part of the axial cylinder which has remained alive, however, frost 

 action is shown in the form of horizontal splits in the pith (Fig. 121 B, I) 

 and a browning which must necessarily retard its functions as a body 

 capable of swelling. These are the reasons why the axis does not elongate 

 again so (|uickly. The spiral ducts {(J) which pass out into the leaves (bl) 



A. Uiaiu'h ol a sweet cherry. The buds, injured by artificial frost, 

 ed and fleshy scales, enlarged and bent away from one another. 

 Liongitudinal section through an injured bud of the branch. 



also appear greatly browned, but tlie parenchyma {p) of the bark body is 

 but little injured and of unusual tenseness. Traces of starch were found 

 here and there at the time of the investigation (June 21). It is clear that 

 the almost fleshy bark body contains an excess of water and nutritive sub- 

 stances and, accordingly, must take over an increased productivity. The 

 greatly increased upward forcing of the water is also to be taken as a 

 cause of the position of the bud bract and the bract-like leaves {bs), both 



