CH. XIl] PROTANDRY. 167 



discharge themselves (as in Silene) before the stigma is 

 ready for pollination, so that while the pollen is being 

 discharged the style is hidden within the anther tube. 

 The two branches of the bifid extremity of the style have 

 not yet opened out into the F like form shown in fig. 74, 

 which would indeed be impossible within the anther tube. 

 The branches of the style are closely appressed to each 

 other; they point vertically upwards and bear at their 

 upper ends a tuft of short hairs (faintly visible in fig. 74 A). 

 The lower part of the style begins to grow in length, 

 so that the pollen is gradually pushed or swept out at the 

 mouth of the anther tube by means of the brushes at the free 

 ends. All this time fertilisation is impossible, in spite of 

 the fact that the end of the style is covered with pollen, 

 because the stigmas are still unripe, and incapable of 

 pollination. As the pollen is pushed out it is carried 

 away by insect visitors and part of it appears adhering to 

 the style, when by continued growth it emerges from the 

 anther tube. The stigmas become receptive and the 

 branches of the style open out as shown in fig. 74. All 

 the various stages of this process may be studied in the 

 flower-head of the dog-daisy. In the centre of the disc 

 are the youngest florets still unopened, further towards the 

 circumference are florets, the anther tubes of which are 

 crowned with emerging pollen, and further still from the 

 centre are seen the extruded styles with widely opened 

 branches. 



