Mutations in Horticulture 625 



the origin of a variety has sometimes been con- 

 sidered as sufficient proof of a sudden origin. 

 The best known instance is that of the renowned 

 cactus-dahlia with its recurved instead of in- 

 curved ray-florets. It was introduced from 

 Mexico into the Netherlands by Van den Berg of 

 Jutphaas, under the following remarkable cir- 

 cumstances. In the autumn of 1872 one of his 

 friends had sent him a small case, containing 

 seeds, bulbs and roots from Mexico. From 

 one of these roots a Dahlia shoot developed. 

 It was cultivated with great care and bloomed 

 next year. It surprised all who saw it by 

 the unexpected peculiarity of its large rich 

 crimson flowers, the rays of which were re- 

 versed tubular. The margins of the narrow 

 rays were curved backwards, showing the bright 

 color of the upper surface. It was a very 

 showy novelty, rapidly multiplied by cuttings, 

 and was soon introduced into commerce. It has 

 since been crossed with nearly all other avail- 

 able varieties of the Dahlia, giving a large and 

 rich group of forms, bound together by the 

 curious curling of the petals. It has never been 

 observed to grow in Mexico, either wild or in 

 gardens, and thus the introduced individual has 

 come to be considered as the first of its race. 



I have already mentioned that the rapid pro- 

 duction of large numbers of new varieties, by 



