LEAVES 



their glossy surfaces all turned up, while those on 

 branches in the tops of trees or shrubs are arranged 

 all around the branch, the glossy surface being 

 turned up. 



What are the reasons for these facts? 



A study of the work of the leaves and the condi- 

 tions necessary for them to perform their work will 

 help us to answer this question. 



THE USES OF LEAVES TO PLANTS 



Experiment. (See Fig. 59). Take a pot or 

 tumbler in which a young plant is growing, also a 

 piece of pasteboard large enough to cover the top 

 of the pot ; cut a slit from the edge to the centre of 

 the pasteboard, then place it on the top of the pot, 

 letting the plant enter the slit. Now close the slit 

 with wax or tallow, making it perfectly tight about 

 the stem. If the plant is not too large, invert a 

 tumbler over it, letting the edge of the tumbler rest 

 on the pasteboard ; if a tumbler is not large enough 

 use a glass jar. If a potted plant is not convenient 

 a slip or a seedling bean or pea placed in a tumbler 

 of water will serve the purpose. Prepare several 

 and place some in a sunny window and leave others 

 in the room where it is darker, and observe them 

 from time to time. In the case of those plants that 

 were set in the sunny window moisture will be seen 

 collecting on the inner surface of the tumbler. 

 Where does this come from? It is absorbed from 

 the soil by the roots and is sent with its load of 



