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. Such 

 reversions invariably occur, according to Wal- 

 lace, in cases of new varieties, which have 

 been produced quickly. But as we now know, 

 such reversions are due to spontaneous crosses 

 with the old form, and to the rule, that the 

 hybrids of such origin are not intermediate, 

 but assume the features of the older of the 

 two parents. In the light of this experience, 

 Metzger 's observation becomes a typical in- 

 stance of vicinism. It relates to the ** Tusca- 

 rora '' corn 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 



