THE CANNA AND CALLA 41 



more lasting. Just now white cannas of very 

 good quality are appearing and every desirable 

 quality in plant and flower are being brought 

 forth from year to year. 



IMPROVED CALLAS (RICHARDIAS) 



The manner of production of my fragrant 

 calla was described in an earlier chapter. 



It will be recalled that this anomaly was pro- 

 duced through selection from an individual found 

 among a large company. 



The question of odor and its variation in 

 flowers was further discussed in a recent chapter. 

 There appears to be, in point of fact, as wide a 

 range of variation among flowers in the matter 

 of odor as in regard to color. But inasmuch as 

 most selective experiments have been made with 

 reference to color and quite without regard to the 

 matter of odor, the cultivated plants have natu- 

 rally developed along the lines of color variation, 

 and even those that were originally fragrant have 

 in many cases lost their perfume. 



IMPROVING ESSENTIAL OILS 



In recent years, however, much more attention 

 has been paid to this matter. In particular, the 

 studies of the chemistry of essential oils, with 

 reference to the production of artificial substi- 



