v.] GENTIANACE^. 127 



it may be more convenient to treat them as true species 

 or as mere varieties, it must at least be admitted that 

 they differ considerably. Not only are they of dif- 

 ferent colours, the one blue, the other red, but A. 

 ccBrulea 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. 



GENTIANACE^. 



In this order we have six British genera : Cicendia, 

 Erythraea, Gentiana, Chlora, Menyanthes, and Lim- 

 nanthemum. 



Gentiana Pneumonanthe is proterandrous. It 

 secretes honey at the base of a tube 25 — 30 mm. long; 

 Bees, however, can creep half way down, in doing 

 which they come in contact with the anthers in 

 younger flowers, and in older ones with the stigma, 

 which lies somewhat higher in the tube. The power 

 of self-fertilisation appears to be lost. Gentiana ama- 

 rella, on the contrary, is homogamous, the anthers and 

 stigma coming to maturity together, though as the 

 style of pistil is somewhat longer than the stamens, an 

 insect touches the stigma before reaching the anthers. 



The beautiful Erythrcea ceritaurium is frequently 

 visited by butterflies, though it contains no honey, at 

 least- neither Sprengel nor Miiller could find any. 



