Kraemer : Color in plants 87 



influence, and which perhaps can not be modified except within 

 certain limits without injuring the plant, still, by reason of the 

 more or less unspecialized character of the protoplasm, the plant 

 is more or less plastic and susceptible of modification in various 

 ways, and who can say just what the limits are in any one 

 direction ? At least we should not allow ourselves to become 

 dogmatic with regard to this problem. As already enumerated, 

 the external factors influencing color in plants are light, tempera- 

 ture, and soil, including certain atmospheric conditions both phys- 

 ical and chemical. When as much work has been done along 

 these lines as in selection and hybridization, we shall probably 

 understand much better than we do now the causes influencing 

 the variation in the colors of plants. 



Artificial coloring of flowers 



A 



in one of the florist's establishments which interested him very 

 much and which he desired to purchase. He then learned that 

 the iris had been artifically colored, and that that particular plant 

 was not for sale. He was, however, able to purchase some of the 

 solution for coloring the flowers, but found to his disappointment 

 on arriving home that the solution did not work. 



Within the past year or two quite a demand has been created 

 for green carnations on St. Patrick's day. During the course of 

 my experiments it occurred to me that it might be possible to take 

 a plant which was deficient in coloring matter and add to it the 

 extracted coloring matter from some other plant. There is a 

 record that as early as 1709, Magnol colored the flowers of tube- 

 roses by placing the stems in the red juice of poke-berries. Even 

 the botanist Unger (1850) stated that the white flowers of the 

 hyacinth could be colored by adding poke-berry juice to the soil. 

 I have been unable to confirm these observations by the use of any 

 natural coloring substance. For nearly fifty years various artificial 

 coloring substances have been used in the study of the ascent of 

 cell-sap. While considerable attention has been given to the ascent 

 of these substances in the stem, not much attention has been given 

 to their effects on flowers, although here and there in the litera- 

 ture one will find a statement with regard to certain effects of this 

 kind. * 



