MAKING NEW KINDS OF PLANTS 



419 



It may be remarked that a curve like that shown 

 in Fig. 238 would indicate that the species was evolving 



il 22 23 2-t 25 Ib 27 ZU 29 *} 31 42 A3 3* 35 it. 37 3639 



238. Asymmetrical curve of variation. 



in the direction of a larger number of rays, since it 

 shows more individuals above than below the type 

 in respect to the number of rays. A curve like that in 



/n 



239. Double curve of variation. 



Fig. 239 would indicate a splitting up of the species into 

 a form with thirteen and a form with twenty -one rays. 



