535 



those appearing first from the bud. On the same leaflet could be found all 

 transitions from deep incisions extending as far as the mid-rib (Fig. io8f ) 

 to the normal undivided leaf surface (Fig. io8/). It was observed on those 

 transitional places that exactly in the middle line of each intercostal field 

 and spread between two parallel, lateral veins, occurred a lighter, colored, 

 transparent stripe along which the tissue was broken in places. (Fig. 108/7.) 

 The edge of such a ruptured place, like the edge of the individual feathery 



Fi.a:. 



108. Horse chestnut leaf, injured in the bud liy frost, and torn, like the teetii 

 of a comb, during unfolding. 



tips of the slits, often shows a somewhat yellowish, harder line, sometimes 

 appearing a little callused. This callused edge consisted of plate cork cells, 

 to which, on the outside, were not infrequently attached rags of dead meso- 

 phyll cells. It is evident from this that the comb-like incisions had not been 

 formed in the bud, but were produced later. 



In the above mentioned, transparent lines, of which the first are broken 

 only in places, the mesophyll is found to be dead on the uninjured part. 

 The cell content was still abundantly present but brown and collected in 



