THE DAHLIA 349 



cases, the tendency to variation became somewhat 

 accentuated. 



The black dahlia and other species of bidens 

 are well worth cultivating, and some other valu- 

 able tuberous flowering plants can be developed 

 from them that would be welcomed by flower 

 lovers in general. 



But other engagements made it impossible to 

 carry the experiments beyond the early stages. 



And as to the matter of crossing the bidens 

 with the dahlia, in which I had been especially 

 interested, the result was altogether negative. 



Repeated efforts failed to fertilize either spe- 

 cies with the pollen of the other. 



Notwithstanding the outward similarity of the 

 plants, it would appear that their racial strains 

 have diverged beyond the point of ready com- 

 mingling. Still it is possible that a more exten- 

 sive series of experiments might have met with 

 better results, and further efforts along the same 

 line are at least worth making. Could a cross 

 be effected, we might reasonably expect some 

 very interesting modifications in the hybrid 

 product ; notably, perhaps, an accentuated capac- 

 ity for growth that would possibly give us 

 dahlias rivaling the largest chrysanthemum in 

 size, as they already rival it in form and flexi- 

 bility of petallike florets. 



