42 RELATION OF THE SIZE OF FLOWER [chap. 



tioned, the curious fact was first noticed that the pistil 

 did not mature until the stamens had shed their pollen. 

 E. aiigustifolmm (Fig. 47) has conspicuous purplish- 

 red flowers, in long terminal bunches or racemes, and 

 is much frequented by insects ; E. parviflorum (Fig. 

 48), on the contrary, has small solitary flowers, and is 

 seldom visited by insects. Now, to the former species 

 the visits of insects are necessary, since the stamens 

 ripen before the pistil, and the flower has consequently 

 lost the power of self-fertilisation. In the latter, on 

 the contrary, the stamens and pistil come to maturity 

 at the same time, and the flower can therefore 



Fig. 47. — EpLlobium aiigusti/oUitm, Fig. 48. — Epilobium parvijlorum. 



fertilise itself. It is, however, no doubt sometimes 

 crossed by the agency of insects; and indeed I am 

 disposed to believe that this is true of all the flowers 

 which are either coloured or sweet scented. 



The genus Geranium also affords us an instructive 

 example. There are a number of species which, as 

 will be seen in Fig. 49, differ nmch in the size of the 

 flowers. Thus those (Fig. 49 a) of Geranium pratense 



