160 LUTHER BURBANK 



individual germ plasm, but the bringing to- 

 gether of different germ plasms from diverse 

 organisms through hybridization. 



For such union of germ plasms there is ob- 

 viously no opportunit)^ in the case of the new 

 plant gi'own from the bulb. 



Hence the fixity of type of plants propagated 

 in this way — a fixity that is often of the utmost 

 practical 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 kind, are in a sense 

 antagonistic or complementary in their influence 

 on the history of the plant itself. 



Propagation by bulbs insures spread of the 

 race and also maintenance of the racial fixity. 



Should environing conditions change, it is un- 

 likely that plants thus propagated could change 

 rapidly enough to adapt themselves to these 

 conditions. 



But at the same time that the plant is produc- 

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

 seeds that are the result of cross-fertilization. 



