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The Improvement of jNIedicinae Plants. 



F A. Miller. 



The ]iriiiciiik'S nl' plant breediiiu; bavt- as yet lianlly Ix-lmi brought td 

 bear upon the inipro lenient of medicinal plants. The necessity of im- 

 provement and ttie possibilities of tlie application of modern methods of 

 lireeding to this group of ])lants has led the writer to undertake a series 

 (■!' investigations upon this subject. A discussion of the results and prog- 

 ress of these investigations is the object of the present paper. 



The broadening influence of plant )>reeding is gradually bringing 

 under control members from all groups of the plant kingdom, and it is 

 only fitting that this very inii)ortant group of plants should be made to 

 yield the best of nature's possilnlities. That the group contains many 

 plastic forms which will yield readily to modern methods of breeding is 

 evidenced Iiy the fact that some of the most potent medicinal forms ap- 

 l^ear in families from which have been obtained many valuable horticul- 

 tural varieties. The Solouaceje for example, with the genera Atropa, Hyo- 

 scyanms. Datura, Solanum and Capsicum, and the no less important Scro- 

 phulariacere containing the now widely known genus Digitalis, which is 

 found to be equally as variable both in cliemical and physical character- 

 istics as the common garden forms derived from the same and related 

 genera, will serve to illustrate this point. 



A review of the literature on drug plant improvement reveals but 

 few attempts at systematic investigation by the employment of standard 

 methods of breeding. On the other hand nuich has been written and no 

 little accomplished upon the introduction and cultivation of medicinal 

 plants. Introduction and cultivation with no improvement has been the 

 order of procedure. It is quite true that some improvement has resulted 

 from a changed environment and a reduced struggle for existence, but not 

 through the intensive application of particular methods. Improvement by 

 means of seed and plant selection, the isolation and testing of favorable 

 varieties, the study of soil and climatic conditions, trials in hybridization, 

 grafting, or other methods which might prove applicable, have not been 

 tried except in comparatively few instances. Had the government made 



