i82 A TEXT-BOOK OF BOTANY. 



feature of color which so often appears when the propagative 

 organs are being brought forth has some connection with definite 

 metaboHc processes, ahhough up till now we cannot recognize 

 what these are." 



Artificial Coloring of Flowers. — Ever since the time of 

 Magnol (1709) there has been considerable interest in the subject 

 of coloring white flowers. A number of aniline dyes can be used, 

 but those belonging chiefly to the azo and rosaniline coloring 

 matters, especially the acid dyes or those used for dyeing wool, 

 give the best result. These dyes are readily soluble in water, and 

 the solutions are made up of a strength of i part of dye to 1,000 

 parts of water. The effects are best seen in white flowers and 

 are produced by allowing the flower-stalks to remain in the solu- 

 tions from one to two hours, when they are placed in water. 

 With some flowers, as the cultivated anemones, the effects are 

 noticeable in from ten to fifteen minutes. Some flowers will take 

 up the dyes better than others. White flowers may be changed 

 to yellow, orange, blue, green, purplish-red or magenta, crimson, 

 purple, salmon-pink or gray by the use of the following dyes: 



1. Yellow flowers are produced by the use of the dye known 

 commercially as " Acid Yellow A. T.," which is chemically the 

 sodium salt of disulpho-diphenylazin-dioxytartaric acid. 



2. Orange-colored flowers may be produced by the use of the 

 dye *' Orange G. G.," which is the sodium salt of benzene-azo-^- 

 naphthol-disulphoriic acid. 



3. Blue flowers may be produced by the use of the dye 

 " Cyanol F. F.," which is the sodium salt of meta-oxy-diethyl- 

 diamido-phenyl-ditolyl-carbinol-disulphonic acid. 



4. Green flowers may be produced by the use of equal parts 

 of the dyes '' Acid Yellow A. T.," and " Cyanol F. F." 



5. Purplish-red flowers are produced by the use of the dye 

 " Acid Magenta," which is the sodium salt of the trisulphonic 

 acid of rosaniline. 



6. Crimson flowers may be produced by the use of equal parts 

 of the dyes '' Acid Yellow A. T." and '' Acid Magenta." 



7. Purple flowers may be produced by the use of equal parts 

 of " Cyanol F. F." and '' Acid Magenta." 



