490 Mutations 



chances of success for the experimental worker. 



In the second half of the seventeenth century 

 (1671), my countryman, Abraham Hunting, pub- 

 lished a large book on garden plants with many 

 beautiful figures. It is called '* Waare Oetfen- 

 inge der Planten," or '^ True Exercises With 

 Plants." The descriptions pertain to ordinary 

 typical species in greater part, but garden- 

 varieties receive special attention. Among 

 these a long list of double flowers are to be seen. 

 Double varieties of poppies, liverleaf {Hepa- 

 tica), wallflowers (Cheiranthus), violets, Cal- 

 tha, Althaea, Colchiciim, and periwinkles 

 (Vinca), and a great many other common flow- 

 ers were already in cultivation at that time. 



Other double forms have been since added. 

 Many have been introduced from Japan, espe- 

 cially the Japanese marigold, Chrysanthemum 

 indicum. Others have been derived from Mexi- 

 co, as for instance the double zinnias. The 

 single dahlias only seem to have been originally 

 known to the inhabitants of Mexico. Thev 

 were introduced into Spain at about 1789, and 

 the first double ones were produced in Louvain, 

 Belgium, in 1814. The method of their origin 

 has not been described, and probably escaped 

 the originators themselves. But in historical 

 records we find the curious statement that it 

 took place after three years' work. This indi- 



