IV.] 



UMBELLIFER^. 



103 



of the numerous small flowers into comparatively 

 large flat heads, by which they are made much more 

 conspicuous : and, secondly, they all secrete honey 

 in the centre of the flower on a flat disk (Fig. 

 84, 85) which is thus accessible to all insects, even 

 those with the shortest lips. This is an advantage, 

 as it effects a considerable saving of time, enabling 

 the insects to visit a given number of flowers 



Fig. 83. — Wild Chervil {CJuerophyllum sylvestre). 



more rapidly, and consequently rendering their fert- 

 ilisation more certain than if they had stood 

 singly. But though the order is so rich in genera 

 and species, it is comparatively uniform, and the 

 divisions are for the most part characterised by the 

 form and structure of the fruit. The flowers are 

 generally small ; the petals five, inserted round a little 



