134 LENTIBULACE&, APOCYNACE&. [CHAP. 



Not only are they of different colours, the one blue, 

 the other red, but A . cczrulea is very decidedly smaller. 

 The stamens and pistil ripen simultaneously. The 

 flowers contain no honey, and partially close about 

 three o'clock in the afternoon. 



The flowers are seldom visited by insects, and it 

 would appear that they generally fertilise themselves. 

 This is said to be the case also with Centunculus 

 minimus. 



LENTIBULACE^E". 



This order contains two British genera : Utricularia 

 and Pinguicula. Both are fertilised by insects, and in 

 both the insect first touches the stigma, and afterwards 

 comes in contact with the stamens. In Utricularia 

 the stigma is irritable and retracts at once on being 

 touched, so that the proboscis after dusting itself with 

 the pollen does not again come into contact with it. 



Both genera are insectivorous. Utricularia is aquatic, 

 and the submerged leaves bear small bladders or 

 utricles, at the entrance of which are stiff hairs so 

 arranged as to permit the entrance, but prevent the 

 exit of small water animals. Even fish, of course only 

 when very young, are sometimes so captured. 



In Pinguicula the leaves are covered with sticky, 

 glandular hairs, and the escape of any small flies or 

 other insects which may be so unfortunate as to 

 alight on them is rendered more difficult by the 

 fact that the edges are curved over. 



APOCYNACE^E. 



In Vinca (the Periwinkle), which has been de- 

 scribed by Delpino and Hildebrand, the arrangement 

 resembles in principle that already described in 



