148 MANUAL OF NATUEB STUDY. 



pupils will notice tliat all these flowers are more or 

 less irregular both as to arrangement of stamens 

 and pistils and as to floral envelopes. They can 

 also be led to see that whenever an irregularity in- 

 jures the chances to self-fertilization it at the same 

 time facilitates insect-fertilization. 



The author is not quite sure that the statement just 

 mentioned is always true, but it surely is true in 

 many cases. For instance, the showy strap-shaped 

 corolla of the sunflower advertises the nectar in the 

 slender tubes of the flowers within, and thus the in- 

 sects are attracted in great numbers. The lower 

 lip of a gamopetalans corolla serves as a resting place 

 for the bee, while it gathers the nectar within. The 

 stamens of the horse-chestnut protrude in such a 

 way as to form a perch for the bumble-bee while 

 he sinks his suction pump down into the nectar, 

 and while doing so, does not pollen cling to his legs, 

 to be deposited upon the stigma of another flower 

 which he is soon to visit ? It will be observed that 

 in such flowers the stigma and anthers of the same 

 flower are seldom ready for fertilization at the same 

 time. The stigma of one flower visited by the bee 

 is withered, and therefore in a non-receptive condi- 

 tion, while the pollen, ready to perform its part in 

 the process of fertilization, clings to the legs of the 

 bee, and is thereby transferred to a receptive stigma 

 in another flower, the stamens of which are not yet 



