272 PRINCIPLES OF PLANT CULTURE 



will of course have to be removed for pollination, after 

 which it should be promptly replaced (Fig. 176). 



Pollination should be performed twenty-four to forty- 

 eight hours after emasculation (441), the period depend- 

 ing upon the plant and the stage of development of the 

 flower at the time of the latter operation (150). Applying 

 the pollen on two consecutive days tends to insure success. 



The pollen is applied by placing an anther (143) con- 

 taining mature pollen in direct contact with the stigma 

 (144), or by removing some of the pollen upon the back 

 of the point of a penknife or by means of a camel's-hair 

 brush, and carefully applying it to the stigma. A pin, of 

 which the head has been flattened by hammering, inserted 

 in the end of a stick, forms a convenient tool for this 

 work. A slender stick of sealing wax drawn to a blunt 

 point may be used in pollination by rubbing it on the 

 sleeve to electrify it. 



The best time for pollination in the open air is often 

 in the early morning, since the atmosphere is then usually 

 still, and contains little pollen from other flowers, which, 

 if freely present in the air, may vitiate the results of pol- 

 lination. 



443. The after-care of crosses. After the last pol- 

 lination, the blossom should again be inclosed until fe- 

 cundation is effected, which is indicated by a rapid en- 

 largement of the ovary. The paper sack may then be 

 replaced by one of mosquito netting. This should be 

 securely, but not too tightly, tied about the stem of the 

 pollinated flower, to protect the inclosed fruit or seed- 

 vessel from injury during growth and maturity, as well 

 as to render it conspicuous. A label should be placed 

 within the sack, or tied on with it, giving the name of 

 the variety whence the pollen was secured. It is also 



