THE FLOWER AND THE BEE 



is only 1 blue. It has been observed that garden-balsams be- 

 come white when ammonia is withheld from the soil, but re- 

 gain their color when it is supplied. Asa Gray is reported to 

 have said that any colored flower might revert to white, and 

 this is undoubtedly true. 



On the other hand, whatever stimulates the growth of a 

 plant, as bright sunlight, strong manures, or crossing, increases 

 the brilliancy of the flowers. When lowland white flowers 

 have been cultivated in the intense light of Alpine summits 

 they have in some cases become red. An application of nitrate 

 of soda will increase the brilliancy of a flower; and tulips, when 

 treated with a strong manure, flush and lose their variegated 

 colors. The brightness of floral hues is also increased by cross- 

 ing. The presence of pigments in the flowers is often correlated 

 with its presence or absence in the leaves and stems; and it is 

 often possible from an examination of the vegetative organs to 

 determine beforehand whether the flowers will be white or not. 

 The white-flowered variety of Portulaca has green stems, while 

 the yellow and red varieties have red stems. A variety of 

 Cyclamen with crimson flowers has the leaves purplish beneath, 

 while the leaves of the white-flowered variety are paler and 

 green on the under-side. The red maple has the flowers, twigs, 

 and young leaves all crimson, while the entire plant of the wood- 

 sorrel, including the flowers and fruit, is frequently red. In 

 Sedum purpureum the petals are purple, and sometimes the en- 

 tire plant; and in the stonecrop (Sedum acre) the foliage is 

 yellowish green and the flowers bright yellow. It is evident 

 that in many species the color of the flowers is determined by 

 the pigment content of the plant as a whole. 



It is easy to understand why white flowers are the most 

 common in nature, and why they are truest to name under 

 cultivation. Naturally florists find that they can develop 



238 



