EXPERIMENTAL EVOLUTION 



533 



later, of two perfectly definite forms which were immedi- 

 ately recognizable as two new elementary species. One 

 of them was a short-styled form: O. brevistylis, which at 

 first seemed to be exclusively male, but later proved to 

 have the power, at least in the case of several individuals, 



Fig, 399. — Yellow daisy, or cone-flower {Rudbeckia sp.), showing varia- 

 tions of the character of mutations in the ray- and disc-flowers. At d 

 the normally ligulate corollas are tubular; at / they have all aborted, 

 except two; at h many of the normally tubular disc-flowers have become 

 ligulate, making a nearly "double flower." (Photo by E. M. Kittredge.) 



of developing small capsules with a few fertile seeds. The 

 other was a smooth-leaved form with much prettier foliage 

 than 0. Lamarckiana, and remarkable for the fact that 

 some of its petals are smaller than those of the parent type, 

 and lack the emarginate form which gives the petals of 



