THE FLOWER AND THE BEE 



the flowers were a deep blue in the morning, changing to beauti- 

 ful deep rose by evening. 



In many species of plants the cell-sap is so nearly neutral 

 that both red and blue flowers may be produced, or both hues 

 may appear in the same flower. Darwin has described a hya- 

 cinth which bore on the same truss a perfectly pink and a per- 

 fectly blue flower, another truss which w^as blue on one side and 

 red on the other, and also flowers which were striped longi- 

 tudinally with red and blue. According to Hildebrand, red 

 and blue cells may occur side by side in the same petal, and in 

 the sweet violet {Viola odoraia) there is a layer of blue cells in 

 the epidermis, under which there is a layer of red cells in the 

 mesophyll. 



Blue anthocyanin is seldom found in yellow flowers, and plants 

 in which the sap is very strongly acid, as the roses, may never 

 produce blue flowers. De Candolle, therefore, concluded that 

 yellow, red, and blue flowers could not occur in the same species; 

 but this doctrine, to use the words of Lindley, "must now be 

 laid up in the limbo of pleasant dreams." This supposed law 

 is contradicted by the hyacinth, pansy, and larkspur {Delphi- 

 nium cardinale). 



Among the Monocotyledons of northeastern America (the 

 series containing the grasses, sedges, lilies, and orchids) there 

 are only 3-t blue flowers, found chiefly in the lily and iris famiHes. 

 It might be supposed that the wonderful orchis family, where 

 the flowers run riot in their strange, bizarre forms, would con- 

 tain many blue flowers; but such is not the fact, and out of 

 6,000 species in the world there is only one, Vanda coerulea of 

 India, which is blue. 



Turning to the Dicotyledons, there are no blue flowers among 

 the apetalous species. This rarity continues among the poly- 

 petalous families, for blue flowers are absent in the poppy, 



252 



