CONCERNING THE CAPACITY OF FOLIAGE LEAVES 
TO WITHSTAND WOUNDING 
ROBERT B, WYLIE 
Foliage leaves are peculiarly liable to injury. From the nature 
of their work they are denied the protection given to older stems 
and larger roots. Their delicate structure not only invites in- 
sects, larvae, and other plant eating animals, but subjects them to 
repeated injury by purely mechanical agencies. Observation of 
leaves as they are found torn and mutilated in nature shows that 
they possess considerable power of adjustment tO' wounds and 
injuries. 
The main object of the experiments outlined below was to find 
out something of the power of foliage leaves to endure severe 
injury and the loss of larger parts, particularly their ability to 
get along after their major venation had been destroyed. It was 
hoped in this way to learn something of the ability of the minor 
venation to meet emergencies involving special demands on their 
capacity for conduction and mechanical support. 
During the summer of 1920 the leaves of a number of plants 
growing on the campus of the Iowa Lakeside Laboratory (on the 
west shore of Lake Okoboji in northwestern Iowa) were sub- 
jected to various types of mutilation. The leaves employed were 
mainly those with pinnate venation (Figs. 49-54), though one or 
two with palmate major veins were used. The list most used in- 
cluded Lilac; Basswood (Tilia americana L.) ; Red Elm (Ulmus 
fulva Michx.) ; Bur Oak (Quercus macrocarpa Michx.) ; Wild 
Grape (Vitis vulpina L.) ; Wolfberry {Symphoriocarpos occiden- 
talis Hook.) ; Four o’clock (Oxyhaphus nyctagineus (Michx.) 
Sweet) ; Solidago rigida L. ; and Milkweed (Asclepias syriaca L.)* 
The latter three plants are herbaceous, while the others are woody. 
These plants all stand on a somewhat sheltered hillside, slop- 
ing to the east, with some protection afforded both by topography, 
adjacent trees, and buildings. However, the area borders on the 
near-by open prairie and is in a region subjected to the drying 
influence of the searching winds of the open country. No attempt 
was made to measur.e the environmental factors since relative 
values were sought at this time rather than quantitative results. 
