128 CAMPANULACE^E. [CHAP. 



is obviously an advantage. From the length of time 

 during which the anthers are ripening, whenever 

 there is a sunny day, and the insects are abroad, they 

 are almost sure to find some anthers ready to dust 

 them with pollen. On the other hand, the stigmas 

 being mature at the same time, they are capable of 

 being fertilized by a single visit. 



Besides the flower-heads with hermaphrodite florets, 

 there are others which contain female florets only, 

 the stamens being more or less rudimentary. This 

 is also an advantage, because if it were otherwise the 

 quantity of pollen would be unnecessarily large. 

 Scabiosa arvensis is visited by a great variety of 

 insects belonging to several orders. . 



Sc. columbaria has a row of distinctly larger ray 

 florets, while the central ones are all of equal size ; 

 the florets also are smaller than in Sc. arvensis ; 

 and consequently, in heads of the same size, more 

 numerous ; the florets appear to be all hermaphrodite ; 

 and the ripening of the anthers does not take place, 

 successively, from the outside. 



CAMPANULACE.E. 



The flowers of Campanula are much frequented 

 by insects, and secrete honey at the base of the bell. 

 The anthers are distinct, the filaments of the stamens 

 are expanded at the base into triangular valves which 

 serve to protect the honey ; the pistil is cleft at the 

 top into two, three, or five stigmatic lobes. The 

 genus is widely distributed and contains numerous 

 species. 



