FERTILIZATION. 



177 



in various stages of maturity, he may investigate its adaptations for 

 insect fertilization and its mode of protecting its pollen from creeping 

 insects and from rain. It will be particularly interesting to compare the 

 various degrees of perfection with which closely related flowers attain 

 these results. Several flowers should be worked out pretty fully and the 

 results of the examination of each recorded in a written account and a 

 series of sketches. Out of the many possible studies of this kind the 

 following are suggested : 



The flower of the pea, the bean, or the locust, consulting Figs. 159, 

 160, 161. 



Fig. 159. —Sweet Pea, Flower, Young Fruit, and Leaf. 



1 II III 



FIG. 160. — I, Diagram of Flower of Sweet Pea. II, Vertical Section of Flower 

 (magnified). Ill, Calyx (magnified). 



