II.] 



LINES AND MARKS ON FLOWERS. 



49 



the pistil matures before any of the stamens. Thus 

 then these four species may be arranged in a table as 

 below : 



Indeed, though further observations on the point 

 are no doubt required, it would seem that, as a general 

 rule, where we find within the limits of one genus some 

 species which are much more conspicuous than others, 

 we may suspect that they are also more dependent 

 on the visits of insects. 



Sprengel also suggests, and, as it would appear, 

 with reason, that the lines and bands by which so 

 many flowers are ornamented have reference to the 

 position of the honey ; 1 and it may be observed that 

 these honey-guides are absent in night-flowers, where 

 of course they would not be visible, and would there- 

 fore be useless, as, for instance, in Lychnis vespertina 

 (Fig. 50), or Silene nutans. Night-flowers, moreover, 



1 I did not realise the importance of these guiding marks until, by 

 experiments on bees, I saw how much time they lose if honey, which 

 is put out for them, is moved even slightly from its usual place. 



