112 COLOUR. 



Green. 



Blue Green. Yellow Green. 



Blue. Yellow. 



Violet Blue. Orange Yellow. 



Violet. Orange. 



Violet Red. Orange Red. 



Red. Red. 



Anhydrated Series. Hydrated Series. 



150. A very remarkable transition of one colour 

 into another is sometimes observed. Meyen saw the 

 petals of the Tamarind white the first day and yellow 

 the second ; though not the beautiful yellow seen in the 

 Compositae. The Hibiscus mutabilis exhibits different 

 tints according to the period of the day, the flowers 

 are white in the morning, rose-red at noon, and dark- 

 red at evening ; but Saggra found that unless the tem- 

 perature was above 66 Fah. they remained white all 

 day. From some experiments made by Korthals upon this 

 plant in the East Indies, he remarks, when speaking of 

 their results, " These observations incline me to believe 

 that the change of colour of Hibiscus mutabilis depends 

 more upon a vital energy proper to the individual itself 

 than to external agents." Oxygenation seems to pro- 

 duce a red chromule in the flowers, or rather causes the 

 chromule, originally colourless, to pass into red. 



151. Meyen saw upon the Cordilleras near Chili, 

 several large shrubs of Colletia spinosa, having both 

 red and white flowers, but the colours were confined 

 to separate branches ; Linnaeus saw blue and white 



