MENDEL AND HIS GARDEN PEAS 



21 



inheritance, and that he expected to find these laws just as 

 surely by studying peas and their descendants as by studying 

 animals and their 

 descendants. 



For the sake of 

 getting clear results 

 he studied characters 

 in pairs or groups, 

 as it were. 



i . The form of the 

 ripe seed — whether 

 round and smooth or 

 angular and deeply 

 wrinkled. 



2. The color of the 

 cotyledon — whether 

 yellow or green. 



3. The color of the 

 seed coat — whether 

 white, gray, or brown. 



4. The form of 

 the ripe seed pod — 

 whether inflated and 

 smooth or constricted 

 between the peas and 

 wrinkled. 



5. The color of 

 the unripe pod — 

 whether green or 

 bright yellow. 



6. The way the flowers grew — whether they were bunched 

 together at the top or scattered along on the stem. 



Color Inheritance in Peas 



A, pod of yellow peas; B, pod of green peas; C, 

 offspring of A and B ; D, offspring of C. Notice 

 that in C yellow is dominant and green recessive, 

 and that green appears again in D, just as white 

 guinea pigs appear among the offspring of hybrid 

 black guinea pigs. (From " Mendel's Principles of 

 Heredity," by W. Bateson) 



