WOUNDING OF FOLIAGE LEAVES 
297 
Fig. 51. Leaves with numerous wounds in the regions between major veins. 
may be seen from the photographs the leaves in these experiments 
were severely injured. 
Results indicate that considerable portions of the blade may 
be removed without, death of remaining parts. Such injuries 
seem always to be local in effect and result in the loss of an al- 
most imperceptible amount of the remaining tissue, due to dry- 
ing of the wounded edges. If, however, in cutting out the blade 
with the punch two areas were cut out so close together as to 
leave an isthmus less than a millimeter in width the living tissue 
thus subjected to water loss from both sides in some cases died. 
In the case of certain Lilac leaves (b, g) one-third of the total 
leaf area was removed, without death of tissue. In Oxybaphus 
(a) the destruction of blade near base of leaf was due to the 
attack of a larva. Grape (c), which is very sensitive to in- 
juries to veins, stood up well in this experiment. 
Measurements showed that in certain Lilac leaves the total 
length of unprotected wounded leaf margin exposed along the 
edges of the wounds was six and one-half times the total dis- 
tance around the leaf. Recalling the conditions of the experi- 
ment it becomes apparent that rarely in nature would leaves have 
to meet such difficult demands. 
IV. U-shaped cuts in leaves {Pig. 52 ). — To test the efficiency 
