16 

 (Guttation). Drops found in morning upon corn and grass "blades. 



0. Supply of food material. if small leaf does not reach its 

 full development. 



9. Nature of conduction. Much the same as food supply but 

 especially applies to water supply. is conduction even ? 



10. Protection. This is negative. 

 a. From exposure to sunlight. 



"b. Protection from excessive transpiration. 



c. Protection from mechanical injury. 



A banana leaf exposed to wind would be torn to pieces. 



d. Protection from animals. 



11. Storage. 



a. Water storage in sand and spit plants. 



b. Air storage in submerged plants. 



e. Storage of starch foods less important. 



12. Absorption of water as in plants of desert regions or in mosses, 

 Also hairs, as in chickweed. Also absorption of inorganic food 

 materials. 



13. Absorption of organic foods, as in the carnivorous plants. 



14. Irrigation. Leaves which catch drippings from other leaves. 

 Spiral arrangement and certain petioles se-am to favor this idea. 



15. Secretion. 



16. Reproduction, only important in lower forms as in ferns. 



17. Protection of other organs, as by the scale leaves. 



18. Mechanical necessity, or- leaf direction, as gravity in lower 

 leaves, pointing downward. 



