58 



pointed out that the experimental re- 

 sults were explicable on the assump- 

 tion that in plants, heterozygous for 

 colour and pollen, the gametes were 

 produced in a series of 16, viz., 7 pur- 

 ple long, 1 purple round, 1 red long, 

 and 7 red round. Purple is associated 

 with long pollen and red with round, 

 but in neither case is the coupling 

 complete. 



In the four Fi families from the cross 

 Blanche Burpee X Emily Henderson 

 (Table II, Exps. 1—4), the distribution 



From one of these Fo families (No. 

 2), ten erect purples were chosen and 



BATESON AND PUNNETT 



of the pollen fits in with this scheme, 

 as the following numbers show: 



grown on in the following year (Nos. 

 5—14). Thev produced: 



The number of round purples and 

 of long reds is in each case decidedly 

 lower than would be looked for on the 

 assumption that the coupling was on a 

 7:1:1:7 basis, and is much nearer 

 to what would be expected if the cou- 

 pling were on a 15 : 1 : 1 : 15 basis. In 



some families, the dearth of these two 

 classes is particularly well marked, and 

 two of them (Nos. 5 and 6) were bred 

 from. From No. 5, five families (Nos. 

 15—19) were obtained, and these, with 

 the present plant, gave the following 

 result: 



The results are irregular. The pro- 

 portion of red longs to red rounds fits 

 fairly well with the supposition that 

 the coupling is on a 7 : 1 : 1 : 7 basis; 

 but the purple rounds are only half as 

 many as would be expected. The cou- 

 pling between long and purple seems 

 to be closer, and is in accordance with 

 the supposition that the gametic series 



is' 15 : 1 : 1 : 15. Both in the F^ gen- 

 eration and in these F4 plants there is 

 evidently some disturbing process 

 which we cannot at present express, 

 though it is possible that we are deal- 

 ing with a mixture of families exhibit- 

 ing the two forms of coupling. 



From the other of the two F^ plants 

 chosen for further experiment (No. 



