LUTHER BURBANK 



For such union of germ plasms there is 

 obviously no opportunity in the case of the new 

 plant grown from the bulb. 



Hence the fixity of type of plants propagated in 

 this way a fixity that is often of the utmost prac- 

 tical importance, as in the propagation of a new 

 race of vegetables or flowers, but which, by the 

 same token, puts the plant thus propagated outside 

 the field of the plant experimenter. 



COMPLEMENTARY MODES OF PROPAGATION 



Thus the two methods of propagation that are 

 available for such a plant as the tigridia and for 

 countless others of its ilk, are in a sense antago- 

 nistic or complementary in their influence on the 

 history of the plant itself. 



Propagation by bulbs insures spread of the 

 race, but insures also maintenance of the racial 

 fixity. 



Should environing conditions change, it is 

 unlikely that plants thus propagated could change 

 rapidly enough to adapt themselves to these 

 conditions. 



But at the same time that the plant is producing 

 new bulbs it may also, year by year, produce seeds 

 that are the result of cross-fertilization. And this 

 method of propagation is a perpetual bid for such 

 variation as will make possible a relatively rapid 

 change in adaptation to a changing environment. 



[102] 



