PHENOMENA OF INHERITANCE 237 



(7) Differences in the length of the stem, 



whether tall or short. 



1. Results of Crossing Individuals with one 

 Pair of Contrasting Characters. — Having de- 

 termined that these characters were constant 

 for certain varieties or species Mendel then 

 proceeded to cross one variety with another, by 

 carefully removing the unripe stamens, with 

 their poUen, from the flowers of one variety 

 and dusting upon the stigmas of such flowers 

 the poUen of a different variety. In this way 

 he crossed varieties of peas which differed from 

 each other in some one of the characters men- 

 tioned above, and then studied the offspring of 

 several successive generations with respect to 

 this character. 



In every case he discovered that the plants 

 that developed from such a cross showed only 

 one of the two contrasting characters of the 

 parent plants, i.e. all were round-seeded, yel- 

 low-seeded, tall, etc., although one of the 

 parents had wrinkled seeds, green seeds, or 

 short stem, etc. "Those characters which are 

 transmitted entire or almost unchanged in the 

 hybridization are termed dominant ^ and those 



