(2) Greater protection from wind. 
2. Mid vein in hickory, walnut, locust, and primary lateral 
veins in Kentucky coffee tree, serve in’ place of ter- 
minal branches of stem. Compare hickory, horse- 
chestnut, ailanthus, walnut and butternut, sumach. 
Advantages of compound leaves. 
Be leicht relation: 
General structure of leaf. 
1. Upper and lower surface cel’s devoid of chlorophyll. 
2. Mesophyll layer of palisade cells beneath epidermis. 
Loose parenchyma with intercellular spaces. 
3. Veins contain conduits for water, salts and food stuffs. 
4. Stomata protected by guard cells. 
Protection of leaves. 
I. Protective modifications. 
I. Structural adaptations. 
(a) Palisade layer of cells acts as light 
screen, aids in lessening loss of 
water. Change in palisade layer 
aS a protection against intense 
light. Compass plant. 
(b) Stomata close to prevent loss of too 
-much water. 
2 SETOCECHIiVel COvering. 
(Ci) orderanis, anda cuttele: 
Thickening of walls. 
Protection against too great loss of 
water. 
Protection against too much water, 
cabbage, carnation. 
(2) Covers of hairs or scales. 
Lessen loss of water vapor. 
Spines protection against animals. 
2, SRedtiction of suriace. 
(1) Reduction of surface with reduction 
of mass: ve \) rer 
(2) Reduction of surface inversely as the 
mass. Lae CD) Ory 
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