MAKING XEW KINDS OF PLANTS 



419 



It may be remarked that a curve like that shown 

 in Fig. 238 would indicate that the species was evolving 



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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 



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239. Double curve of variation. 



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

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



