256 



BRITISH FLOWERING PLANTS 



exposing the pollen, which is gradually carried off by 

 the insects visiting the flowers for the sake of the nectar 

 (Fig. 160). This is the second stage. When the hairs 

 are all withdrawn the stigmas open out, and are ready 

 to receive pollen (Fig. 161). This is the third stage. 

 Fourthly and finally, in the absence of insect visits the 

 stigmas bend over and dust themselves with any pollen 

 which may be remaining on the pillar of the pistil. 



The fruit is a three - celled capsule. The seed 

 capsules are in some species erect, in others hanging. 

 The former open at the apex, the hanging ones at 



Fig. 159. Fig. 160. Fig. 161. 



Figs. 159-161. — Campanula medium. Fig. 159, section of bud ; Fig. 160, section of 

 flower in first (male) condition ; Fig. 161, section of flower in second (female) 

 condition, a, anthers ; ca, calyx ; co, corolla ; /, filaments of stamens ; jo, style 

 with stigmas ; po, pollen. 



the base. Thus in both cases the opening is at the 

 actual upper part of the capsule. I have suggested 

 that the object is to provide for the dispersal of the 

 seeds. The result is, that they do not fall directly 

 out of the capsules, but remain in them until on some 

 windy day the capsules are swung backwards and for- 

 wards, and eventually scatter the seeds. In the hanging 

 capsules the method by which the valves at the base 

 open is very peculiar. In C. medium, for instance, the 

 inner face is very much thickened and lignified. The 

 thickened portion is ovate, and drawn out into a long, 

 acuminate neck, extending up into the capsule ; the 

 broader end is at the base of the capsule, and corresponds 



