90 



PLANTS MAKE FOOD 



another so as to present their upper surface to the sun. Such an 

 arrangement is known as a leaf mosaic. In the case of the dande- 

 lion, a rosette or whorled cluster of leaves is found. In the horse- 

 chestnut, where the leaves come out opposite each other, the older 

 leaves have longer petioles than the young ones. In the mullein 

 the entire plant forms a cone. The old leaves near the bottom 

 have long stalks, and the little ones near the apex come out close 



A lily, showing long narrow 

 leaves. 



The dandelion, showing a whorled ar- 

 rangement of long irregular leaves. 



to the main stalk. In every case each leaf receives a large amount 

 of light. Other modifications of these forms may easily be found 

 on any field trip. 



Starch made by a Green Leaf. - - If we examine the palisade 

 layer of the leaf, we find cells which are almost cylindrical in form. 

 In the protoplasm of such cells are found a number of little green- 

 colored bodies, which are known as chloroplasts or chlorophyll 

 bodies. If we place the leaf in wood alcohol, we find that the 

 bodies still remain, but that the color is extracted, going into the 

 alcohol and giving to it a beautiful green color. The chloroplasts 

 are, indeed, simply part of the protoplasm of the cell colored green. 

 These bodies are of the greatest importance directly to plants and 

 indirectly to animals. The chloroplasts, by means of the energy re- 



