False Atavism 205 



immediately have been observed, had it oc- 

 curred, because the hybrids between the cruci- 

 ate and the normal flowers are not intermediate, 

 but bear the broad petals of the 0. biennis. 



We may now take up another phase of the 

 question, that of the running out of new varie- 

 ties, shortly after their introduction into a new 

 country, or later. 



The most widely known instance of this is 

 that of the American corn in Baden, recorded 

 by Metzger and quoted by Darwin as a remark- 

 able instance of the direct and prompt action 

 of climate on a plant. It has since been con- 

 sidered as a reversion to the old type, in which 

 return to mediocrity invariably occurs, accord- 

 ing to Wallace, in cases of new varieties, 

 which have been produced quickly. But as we 

 now know, such reversions are due to spontan- 

 eous crosses with the old form, and to the rule, 

 that the hybrids of such origin are not inter- 

 mediate, but assume the features of the older 

 of the two parents. In the light of this exper- 

 ience, Metzger 's observation becomes a typical 

 instance of vicinism. It relates to the ' * Tusca- 

 rora " com of St. Louis, a variety with broad 

 and flat white seeds. 



About the year 1840, this corn was introduced 

 into Baden in Germany, and cultivated by Metz- 

 ger. In the first year it came true to type, and 



