F. Kbbble and C. Pbllew 55 



that most of the thick-stemmed plants with short or long internodes, 

 are late (141 late, 6 early); that, of the thin, sliort-noded plants, 6 are 

 early and 7 late, and that of the thin, long iiiternoded plants, 24 are 

 early and 8 are late. It is therefore apparent that there is a relation 

 between morphological, vegetative characters and period of flowering. 

 Thick-stemmed plants contain a very high proportion of late plants, 

 thin-stemmed plants contain an almost equally large excess of earlies. 

 As has been shown by Bateson, departures from normal, Mendelian 

 expectation which manifest themselves by discriminate distribution of 

 a character among the members of a generation, may be interpreted by 

 the aid of the hypothesis of gametic coupling. Applying this hypothesis, 

 and assuming that the coupling between thick stem and late factor is 

 of the 7:1:1:7 order (Bateson, 1909, op. cit. p. 159), we arrive at 

 the following results : — 



Calculated on trihybrid scheme 



Observed 



Calculated on 7 : 1 coupling ... 



!r= thick stem, L- 



Though the numbers are not large enough to demonstrate the exist- 

 ence of 7 : 1 coupling between thick stem and late flowering factor, yet 

 their general run and fairly close approximation to those expected on 

 the basis of such coupling make it probable, in our opinion, that these 

 two factors are connected with one another in this manner. 



The nature of the influence exerted by the long-stem factor in 

 inducing precocity of flowering we are not yet prepared to discuss, nor 

 can we deal with the general physiological problems suggested by these 

 observations ; but will content ourselves with pointing out that, before 

 a full analysis of physiological properties such as those of time of 

 flowering can be made, a not inconsiderable amount of breeding work 

 must be done with the preliminary object of obtaining suitable material, 

 i.e. material which consists of groups alike in all respects save in the 

 one which it is proposed to investigate. We learn from the foregoing 

 preliminary experiments that it is not enough to cross any late with 

 any early pea, for, as is indicated by these experiments, lateness and 

 earliness are connected, in a manner not to be suspected on a priori 

 grounds, with definite, morphological, vegetative characters. 



The authors have pleasure in acknowledging that in carrying out 

 their experiments they have been aided by a grant from the Royal 

 Society. 



