CHAPTER XII. POLLINATION AND FERTILIZATION. 



97 



same plant in the pistillate stage, when the anthers have dis- 

 charged their pollen and the style has lengthened, unfolding its 

 stigmatic lobes and occupying such a position as to come in 

 contact with the back of the insect when she enters the flower. 



The flower has two stamens, separately represented in Fig. 

 291, inserted in the throat of the corolla in such a position that 

 the insect, in order to reach the nectar, must pass between them. 

 Each anther has a long, curved connective, which is pivoted near 

 its middle to the apex of the filament. One lobe, the upper one 

 in the undisturbed flower, is fertile, and the other sterile. Fig. 

 291 represents them as they are in their normal position, and 

 Fig. 292 as they are when a bee passes between them, butting 

 her head against the sterile lobes, pushing them forward and 



Fig. 292. 



Fig. 291. 



Fig. 291. — Position of stamens of Sage, when undisturbed. 



Fig. 292. — Position of anthers, when a bee passes between the stamens to reach the 

 nectar. 



upward, and turning the fertile lobes backward and downward. 

 It is evident that the insect visiting the flower in its staminate 

 stage will get the back and upper portion of her hairy body 

 dusted with pollen from contact with the fertile lobes, and in 

 flying away to a flower which is in the pistillate stage, will bring 

 the same part of her body into contact with the stigmas. 



Another interesting instance among the hundreds that might 

 be mentioned occurs in Habenaria ciliaris, one of our most 

 beautiful orchids. Fig. 293 represents one of the flowers of this 

 plant. In the centre of it is the column of combined pistils and 

 stamens, a. The stigma lies centrally between the anthers, each 



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