New Species of Oenothera 519 



others have formerly mutated in this way, oth- 

 er species must at present be in the same 

 changeable condition. And if mutations in 

 groups, or such periodic mutations should be 

 the rule, it is to be jiremised that these periods 

 recur from time to time, and that many species 

 must even now be in mutating condition, while 

 others are not. 



It is readily granted that the constant condi- 

 tion of species is the normal one, and that mu- 

 tating periods must be the exception. This fact 

 does not tend to increase our prospect of dis- 

 covering a species in a state of mutability. 

 Many species will have to be tested before find- 

 ing an instance. On the other hand, a direct trial 

 seems to be the only way to reach the goal. No 

 such special guides as those that led us to the 

 choice of pelories and double flowers are avail- 

 able. The only indication of value is the pre- 

 sumption that a condition of mutability might 

 be combined with a general state of variability 

 at large, and that groups of plants of very uni- 

 form features might be supposed to be constant 

 in this respect too. On the contrary, anomalies 

 and deviations, if existent in the members of 

 one strain, or found together in one native lo- 

 cality of a species might be considered as an 

 indication in the desired direction. 



Few plants vary in the wild state in such a 



