308 LATE ORIGIN OF BLUE FLO^^^HS 



justify us in concluding that blue flowers were formerly 

 yellow or white ? Let us consider some of the orders 

 in which blue flowers occur with others of difierent 

 colours. 



For instance, in the Ranunculaceae,' those with 

 simple open flowers, such as the buttercups and Thalic- 

 trmns are generally yellow or white. The blue 

 delphiniums and aconites are highly specialised, 

 abnormal forms, and doubtless, therefore of more recent 

 origin. Among the Caryophyllacea3 the red and purplish 

 species are amongst those with highly specialised 

 flowers, such as Dianthus and Saponaria, while the 

 simple open flowers, which more nearly represent the 

 ancestral type, such as Stellaria, Cerastium, &c., are 

 yellow and white. 



Take again the Primulaceae. The open-flowered, 

 honeyless species, such as Lyaimachia and Trientalis, 

 are generally white or yellow ; while red, purple, and 

 blue occur principally in the highly specialised species 

 with tubular flowers. The genus Anagallis here, how- 

 ever, certainly forms an exception. 



Among the violets we find some yellow, some blue 

 species, and Miiller considers that the yellow is the 

 original colour. Viola hijiora^ a smaU, comparatively 

 little specialised fly-flower, is yellow ; while the large, 

 long-spurred V, calcaratay specially adapted to humble- 

 bees, is blue. In V. tricolor, again, the smaller 



' I take most of the following facts from MiUler's admirable 

 work on Alpine Flowers. 



