Inheritance in the Higher Plants 85 



is the direct ancestor of Johannsen's genotype conception 

 of heredity. 



Other items of fact and improvements upon technique 

 were numerous then as they are today, but these few dis- 

 coveries comprise the only notable contributions of the 

 hybridizers until Abbot Mendel's epoch-making researches 

 on the pea (Pisum sativum) in the little cloister garden at 

 Brunn. 



The elements of Mendelianism as they apply to animals 

 have already been discussed. In taking up some of the 

 important neo-Mendelian facts as they are found in the 

 higher plants, I propose to describe types of Mendelian 

 inheritance with the idea of showing how facts that are 

 apparently non-related may be included under one descrip- 

 tive notation. The illustrative material is drawn largely 

 from my own pedigree cultures of maize or Indian corn 

 because they are naturally more familiar, but the points 

 discussed by no means apply only to corn. 



It is of no small importance that strict Mendelian nota- 

 tion has been found to apply to the facts of inheritance in 

 both plants and animals. Sex has arisen separately in both 

 kingdoms, and probably even more than once in the vege- 

 table kingdom. It is therefore a great argument for the 

 universality of Mendelian inheritance in sexual reproduc- 

 tion that the general facts are so similar in both types of 

 organisms. If many facts in each kingdom can be included 

 in the Mendelian conception of heredity, the probability 

 that it is a truth of universal scope increases by geometrical 

 progression. Let us see whether or not this is true. 



Let us examine first a simple case of monohybridism, 

 i.e., a case where the parents differ by but one character. 

 Such a character distinguishes sweet corn from starchy corn. 



