Kraemer : Color in plants 89 



9. Gray flowers may be produced by the use of the dye 

 " Naphthol Black B., M which is the sodium salt of disulpho-B- 

 napthalene-azo-A-napthalene-azo-B-naphthol-disulphonic acid. 



I have also tried feeding these solutions to the growing plants, 

 and found that carnations growing in an artificial soil, the basis of 

 which is sand, will take up the solutions and show the effects in 

 the flowers. The dyes are taken up chiefly through the tissues 

 of the veins and are gradually diffused in the adjoining cells. The 

 plants are not injured by the solutions, and if they are properly 

 used neither the texture nor odor of the flowers is affected. 



While the artificial coloring of flowers in the manner described 

 is of more or less interest from the scientific point of view, it has 

 also a practical application. In decorative schemes where a par- 

 ticular color is selected this method could be used for producing 

 flowers all of one color, such as blue roses, blue carnations along 

 with violets and other blue flowers. Or in some instances, where 

 the demand for flowers of a certain color is greater than the sup- 

 ply, artificially colored flowers could be produced from white 

 ones. 



These dyes may also be used to intensify flowers having a pale 

 color at this season of the year, as pale-yellow carnations, pale- 

 pink roses, pale-yellow snap-dragon, etc. In some cases the natural 

 colors can be modified, as in the production of yellowish-red flowers 

 of snap-dragon from yellow flowers. In the production of novel- 

 ties, as in the production of green carnations and green roses, the 

 method can be utilized. The color produced by Naphthol Black 

 B. is a delicate gray or grayish-black, and it has been suggested that 

 roses and carnations colored with this dye would furnish appro- 

 priate mourning flowers. Another use of these dyes is in the 

 coloring of wild flowers for decorative purposes. For example, 

 wild carrot when colored with a blue dye gives a beautiful effect, 

 being suggestive of a head of forget-me-nots. 



The colors of flowers so dyed are permanent, and the dried 

 flowers can in some instances be used for ornamental purposes, as 

 in the case of hydrangeas, which are frequently used in the dried 

 condition. There may be a possible application of these results; 

 in the manufacture of artificially colored dried flowers and plants 

 for decorative purposes. 



