262 



FLOWERS 



positions. There is a certain thing which must be accom- 

 plished before good seeds can be produced, and it is 

 chiefly for the accomplishment of this certain thing that 

 the visible parts of flowers appear to be designed. That 

 certain thing which must be accomplished is pollination. 



You have already heard of pollen (see page 60). It 



is that dust-like substance, usually yellow, which comes 



. , ,„ ., from the inner 



'^^^^Mi^i part of the 



flower. You 

 know that be- 

 fore seed can be 

 produced, this 

 pollen must be 

 transferred ; it 

 must go from 

 the anthers in 

 which it is pro- 

 One of duced to the 

 stigmas. Once 

 upon the stigma, the pollen grain produces a structure 

 which is very important in seed making, as you shall see. 

 It is this transfer of pollen from anthers to stigmas which is 

 called pollination. To secure this transfer appears to be the 

 principal aim of the flower. Other processes are equally 

 important in seed production, and with them the flower is 

 also concerned, but these other processes are hidden. Pol- 

 lination is very plain. It is the evident, external process 

 to which flowers appear to be devoted. It is the principal 

 key to an understanding of the forms of flowers and of the 

 positions which they assume. 

 Pollination is of two kinds. Pollen may be transferred 



Fig. 93 E. — Chokeberry (Prunus arbutiJoUa) 



the common spring-flowering shrubs of the rose family. 



