340 ALTERATIONS OF COLOUR. 



the petals, the others being of their ordinary green 

 colour. 



The occuiTence of coloured bracts, as in Poinseitmi 

 BougainviUeaf &c., is very common under natural con- 

 ditions, and need not here be further alluded to. 



Increased intensity of colour often accompanies 

 teratological changes ; an instance has just been alluded 

 to in the Gesnera: the feather hyacinth, Mnscari 

 comosnm,, furnishes another illustration, the adven- 

 titious pedicels being brightly coloured. 



In fasciated stems, also, of herbaceous plants, it not 

 un frequently happens that the upper portions of the 

 stem are brightly coloured. 



The occurrence of flowers or fruits of different colours 

 on the same plant, or even in the same cluster, is a 

 phenomenon which does not come within the scope of 

 the present book ; the reader may, however, be referred 

 to the excellent summary on this subject published by 

 Mr. Darwin in his work on the * Variation of Animals 

 and Plants under Domestication.' 



