POLLINATION AND FERTILISATION 29 



Examples ax-e to be found among the Primulas, and in the Purple 

 Loosestrife, both of which are described in thek place. 



In some flowers the stamens are irritable, rising in such a manner 

 as to strike the insects that visit them ; and in these cases the 

 anthers almost invariably deposit pollen on that portion of the 

 insect's body which is most hkely to come in contact with the 

 stigma of the next flower visited. Again, in Sages, the anthers are 

 so arranged that they are made to swing, as on a see-saw, to exactly 

 the same end. 



These few examples will suffice to show that the structure and 

 conformation of flowers are subservient to the one great purpose 

 of securing the most suitable means of the distribution of pollen, 

 and the student who recognises and studies the various forms of 

 flowers in this connexion will find his work in the field doubly 

 interesting. 



