No. 439.] NORTHERN GA MOPE TA LOUS FLOWERS. 465 



act as leaves. A similar change has been observed in 

 orchids and liliaceous plants. Virescence, or the occurre 

 green flowers instead of those of the normal color, has 

 observed in many Ranwiculaceas, Umbelliferae and Compx 

 The formation of chlorophyll has but to cease, and imdt 

 action of light the petals will quickly lose their green color 

 the result that in most instances the flower will change to ; 

 or white. If the yellow pigments, which are invariably \ 

 ated, as has been shown, with the chlorophyll in the chloro 

 arc persistent and continue to increase, the color of the : 

 will be yellow. The quantity of yellow pigments, it will be r 

 bered, varies greatly in different plants. In some the 

 scarcely perceptible, in others they are so abundant as to 

 the whole plant yellow, while in a few golden yellow specie: 

 exclude all other pigments even the chlorophyll. If, hov 



