172 FIRST STUDIES IN PLANT IJFE 



carbon and lime, into living foods. 6-10. The leaf cannot travel 

 to seek food. 7-10. The leaf under the microscope : upper skin of 

 water cells ; two rows of long cells below, where the stuffs of 

 which the plant is built are made ; looser cells where water leaves 

 the leaf through breathing-pores in the lower skin. 



XL— The Leaves.— Part III., p. 63. 



1-2. Starch in a potato. 3. A white leaf can make no starch. 

 4. Nor can one that gets no sunlight. 5-6. The sun-force at work 

 in a plant. 7-8. The leaf uses up carbon and gives out oxygen. 

 9-10. Experiment to show that leaves give oflf water. 



XII.— Leaves— Shapes and Vein-plans.— P. 68. 



1-2, The leaf -stalk ; rarely round. 3-4. The leaf -blade : flat 

 and broad ; long and narrow ; network of leaflets ; appearance on 

 each side. 5. The skeleton : sap-tubes, veins. 6. How the root- 

 sap spreads over the leaf. 7. How the leaf-sap returns to the 

 stem. 8-13. Shapes: feather-like, palm-like; entire, saw-edged, 

 toothed, lobed, dissected ; heart, egg, spear-head, arrow-head, 

 hair-like, shield, etc. 14. Opposite leaves ; the whorl. 

 15. Smooth, hairy, rough, soft, velvety. 16. Simple, compound. 



XIIL- Leaves.— Reasons for Leaf Shapes. — P. 78. 



1-3. The grass-leaf type : one seed-leaf. 4-6. How light 

 shapes the leaves ; narrow in scanty light. 7. How the leaves 

 differ on the same plant. 8. The original home of the tree must 

 be considered : umbrella-tree. 9-10. Plants that alter their leaves 

 as they grow older : gum-tree. II. The first leaves of the black- 

 wood tree. 12. How sap-flow shapes the leaf : ivy. 13. Leaves 

 that catch flies : sundew. 



XIV.— How Leaves Protect Themselves.— p. 86. 



1-3. How leaves are protected from cold : clover, gum sapling. 

 5-6. Protection from heat : by storing water, e.g., purslane, stone- 

 crops, cactus ; by checking loss of water, through hard skin, 

 curled leaves, salted sap, haii-y coat, or spray of perfume. 

 7-10. How leaves are guarded against animals : by lying flat, 

 dandelion ; by unpleasant taste ; by thoi-ns, spines and hairs, 

 thistle, gorse, nettle. 



