ARTIFICIAL POLLINATION 301 



ready to receive pollen, and the mode and time of dehiscence of 

 the anthers when the pollen is mature, is useful. 



The receptive surfaces of the stigmas of flowers when mature 

 are often moist or sticky : in other cases they enlarge and appear 

 rough and covered with very small round prominences when 

 viewed with a lens. Where the stigmas are bifid the two halves, 

 which in an immature state lie close together, separate and curl 

 away from each other when mature. 



The details of the actual method of cross-pollination varies 

 with the structure and arrangement of the flowers to be operated 

 upon, and also to some extent upon the taste and fancy of 

 the operator. The following plan gives excellent and accurate 

 results : — 



(i) First select the flower to be used as the seed-bearer. This 

 must be done before the flower has opened and before its own 

 anthers are mature enough to shed their pollen. Unless this 

 precaution is adopted self-pollination or cross-pollination by 

 agency of the wind or insects may have already taken place. 



Where several flowers are borne somewhat close together as 

 in the apple and wheat, one or two only should be crossed and 

 the others removed, so that the crossed specimens may have a 

 better chance of developing. 



(ii) Open the flower and carefully remove the stamens with 

 fine-pointed forceps taking hold of each stamen by its filament 

 so as not to crush the anther and thereby run the risk of setting 

 free the pollen. 



Where the stamens are epipetalous and in other instances it 

 is sometimes more convenient to cut off the calyx, corolla, and 

 stamens with fine scissors. Be careful not to touch or injure 

 the style and stigma of the gynsecium. 



After this process of emasculation or removal of the male 

 sexual organs, the flower or the shoot bearing it must be 

 enclosed in a paper bag tied up at the mouth so as to exclude 



