Repeated Mutations Due to the Same Causes. 467 



of any single seed-parent. If some mutants were absent, 

 others were more numerous to make u]) for it. 



The power to mutate is also inherited by the new 

 species. We have already seen several examples of this 

 in § 8 and later in §§ 10-23. For instance O. seiutillaiis 

 is very mutable: it produces pretty regularlv 10-207t' 

 ohlonga; about %% O. lata and about %% 0. nauella 

 (p. 244). O. ohlonga, O. nanella, O. leptocavpa and 

 others gave also rise pretty regularly to the other muta- 

 tional forms in proportions not very different from those 

 in which they are produced by 0. Lauiarekiana itself 

 (§8). And the same is true of crosses, for example 

 between 0. lata and 0. nanclla, 0. ruhrinervis and O. 

 nanella and so forth. 



Therefore, when a character passes from it^ latent 

 to its active condition, all or apparently all of the other 

 characters latent in it remain so. They are not lost in 

 the process. 



The question arises : are they ever lost ? 



0. hrevistylis and 0. laevi folia seem to afford an 

 answer to this question. They grew in 1887 in the field 

 at Hilversum, they are not known anywhere else and, 

 what is more to the point, they have not been observed as 

 mutants a single time in my cultures, even in cultures of 

 many thousands of individuals. It is therefore possible 

 that they no longer exist in my species in a latent con- 

 dition. 



It is, of course, possible that my plants may not have 

 descended from the same individual ancestors as those 

 from which these two species arose. So that my obser- 

 vations do not afford a definite proof that the latent char- 

 acters of these species have been Jost. But, inasmuch as 

 the whole lot of the Oenotheras in the wild locality has 



