LUTHER BURBANK 



surer and more effective. Inasmuch as the bee 

 has no conscious share in the plant's solicitude 

 to effect cross-fertilization, it has been found 

 expedient on the part of many flowers to adjust 

 the arrangement of stamens and pistils in such a 

 :way that the visiting insect shall surely receive a 

 modicum of pollen, yet cannot rub this pollen 

 against the stigma of the same flower. 



Some illustrations of what might be called 

 extreme measures to prevent such inadvertent 

 self-fertilization, were given earlier in the present 

 chapter. Let us note a few additional instances, 

 with reference in particular to flowers that are 

 largely poUenated by the bee. 



A simple and effective method of guarding 

 against self-poUenation we have seen illustrated 

 in the common geranium (Pelargonium). 



When the geranium flower first opens, a little 

 cluster of anthers may be seen on the tip of the 

 erect filament in the center of the bright, showy 

 flower. At this stage the undeveloped stigma lies 

 closely folded up and wholly unreceptive among 

 the stamens. But soon after the pollen has been 

 shed or gathered, the anthers drop off; then the 

 stigma spreads out its five receptive lobes from 

 the tips of the connecting filaments, and is ready 

 to receive pollen from another flower. 



In the snap-dragon flower, and in many other 



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