Variation and Heredity 479 



to get no indication of a particular method in heredity, 

 and no possible analysis of the independent characters 

 concerned. As a matter of fact, in Mendelian inherit- 

 ance, subsequently discussed, it will be apparent that 

 certain ancestors may contribute nothing, or some few 

 characters only. 



292. Types of inheritance. There are apparently 

 several distinct types of hybrid inheritance, such as 

 blended, intensified, mosaic, heterogenous, and alternative. 

 Three of these may be briefly characterized as follows : 



1. Blended inheritance. The crossing of forms dis- 

 tinct with respect to any character yields offspring pos- 

 sessing this character to a degree intermediate between 

 the parents. Some cases of apparent blends are ques- 

 tioned, and much more study of this type is required. 



2. Intensified inheritance. The crossing of forms dis- 

 tinct with respect to any character (e.g. size) yields off- 

 spring possessing that character more highly developed 

 than either parent. Certain plums produced by Burbank 

 are apparently of this type. 



3. Alternative inheritance. The crossing of forms 

 distinct with respect to any character yields offspring 

 which resemble one parent only ; but the hybrid nature of 

 this first generation is shown by its offspring. In the latter 

 there is segregation, as explained later, in such manner 

 that each character appears practically unchanged in a 

 part of the offspring. 



293. Recent studies. The newer studies upon heredity 

 practically began with the new century, and with the 

 rediscovery of work done nearly half a century earlier. 

 These investigations are in a large measure concerned 



