78 Reduplication Series in Stveet Peas 



have arisen, especially during the present summer, and several years 

 must necessarily elapse before they can be settled satisfactorily. 



The work recorded in the following pages deals with the inheritance 

 of six factors, viz. : 



B the factor for blue as opposed to red. 



E „ „ erect standard as opposed to hooded. 



L „ „ long pollen „ „ round. 



D „ „ dark axil „ „ light axil. 



F „ „ fertile anthers „ „ sterile. 



N „ „ normal flower „ „ cretin. 



As pointed out elsewhere ((4), p. 4) the relation between the factors 

 B, E, and L is such that a plant which is heterozygous for any pair of 

 this series shews coupling or repulsion according as the mating is 

 AB X ab, or Ab x aB. Until the present summer (1913) the experi- 

 mental evidence was in favour of regarding this generalisation as true 

 also for the series D, F, N, and to some extent it certainly is true. But, 

 as will appear later, there are grounds for supposing that under certain 

 conditions, hitherto undetermined, a simple Mendelian relation, without 

 coupling or repulsion, is to be found for this trio of factors. In this 

 connection it is interesting to recall Baur's work with Antirrhinum 

 (1) suggesting that in this genus coupling may result from the cross 

 AB X ab, while for the same pair of characters the mating Ab x aB 

 may give an ordinary Mendelian result. In considering the data given 

 in the present paper, those relating to the B, E, L series will be taken 

 first. 



A. The B, E, L Series. 



(1) Tlie relation hetweeii B and L in plants Jiomozygous for 



E or e. 



(a) Nature of mating BL x bl. 



This was the reduplication series first discovered, and the nature 

 of the F^ generation can be explained on the hypothesis that F^ 

 plants made in this way produce a series of gametes of the form 

 7BL:lBI:lbL:7bl. To the evidence already given, derived from F., 

 families ex Emily Henderson long pollen x E. H. round pollen ((2), 

 p. 36), can now be added 4 further F^ families (Table I, A), 40 F.^ 

 families (Table I, B), and 14 families (Table I, C) derived from various 

 crosses inside the E. H. strain. The entire material was homozygous 



