v.] CAMPANULACEM. 121 



being mature at the same time, they are capable of 

 being fertih'zed by a single visit. 



Be^des 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 differs from Sc. arvensis as already 

 mentioned in having a row of distinctly larger ray 

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

 in having five lobes to the corolla instead of four ; 

 the florets also are smaller ; 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. Why should there be these difi^erences 

 in species otherwise so nearly allied .-' 



CAMPANULACE^. 



The genus Campanula takes its name from the 

 tubular, bell-shaped corolla, which terminates in five 

 broad or lanceolate lobes'. The flowers 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 trian- 

 gular valves, which serve to protect the honey ; the 

 pistil is cleft at the top into two, three, or five stig- 

 matic lobes. The genus is widely distributed and 

 contains numerous species. 



