94 



LOCK : PRESENT STATE OF 



\ 



The characters of wliich the hereditj^ has been studied are 

 dealt with here in the following order : — 



(1) The shape of the cotyledons. 



(2) The colour of the cotyledons. 



(3) The colour of the testa, corolla, and leaf axils 



(4) Characters of the pod. 



(5) The presence or absence of fasciation. 



(6) Habit of growth. 



(7) Duration. 



In conclusion, some miscellaneous points will be touched 

 upon, which have less direct bearing upon problems of 

 heredity. 



1. — Shape of the Cotyledons. 



A. — External Characters. 



(i.) Round and wrinkled. — This is the simplest of the pairs 

 of external shape characters. On crossing, round is fully 

 dominant over wrinkled. To this rule there does not seem to 

 have been recorded any well-authenticated exception in which 

 healthy plants were concerned. In F 2 upon 153 plants Mendel 

 found 7,324 seeds, of which 5,474 were round and 1,850 

 wrinkled. This result and the results of other observers are 

 tabulated below in order to facilitate reference : — 



Shape of Seeds. 

 Observer. 



F 2 



Mendel (16) 

 Tschermak (17) 

 Bateson (2) 

 Hurst (11) 

 Lock (14) 



F 3 



. Tschermak (17) 

 Lock (14) 



F4 .. Lock (14) .. 2,328 .. 812 . . 25-8 



There is no sensible difference between the ratios found in 

 F 2. F 3, and F 4. In the experiments at Peradeniya the 

 distinction between round and wrinkled was, if anything, 

 sharper in F 4 than in F 2. The ofifspring of the heterozygotes 



