4 Varietäten, Descendenz, Hybriden. 



light axilled plants was crossed with the white Emily Henderson 

 (round pollen). The only recessive characters (apart from the light 

 axil which was present in both parents) which appeared in the F 2 

 generation from this cross were those which were known to have 

 come in from the E. H. parent. The wild plant must therefore be 

 regarded as homozygous for all the factors dominant to these. 



Stocks, (p. 35—40). 

 Considerable additional knowledge has been obtained regarding 

 the circumstances under which plants with double flowers may be 

 expected to occur. It is scarcely doubtful that the double character 

 is inherited in a definite and regulär manner, and independently 

 of external conditions. Experiments already recorded have shown 

 that in most of the Ten-week Stocks, in the Red and White English 

 Brompton Stocks, and probably also in the East Lothian strains, 

 the Singles are of two kinds: 1. those which on self-fertilization 

 yield only Singles; and 2. those which similarly treated, give a 

 mixture of Singles and doubles, the latter being usually in distinct 

 excess of the former. The results of the present experiments go to 

 show that from a non-sporting individual only non-sporting offspring 

 are obtained; whether self-fertilized or bred inter se such offspring 

 appear incapable of throwing doubles. Conversely, Singles derived 

 from a plant belonging to the sporting group have, so far as expe- 

 riment has yet gone, proved themselves to be all of the sporting 

 class, giving again both Singles and doubles. 



Two of the Ten-week strains however differ from those enu- 

 merated above in that in each case the race as a whole appears to 

 be ever-sporting; not one of 110 individuals tested was found to 

 breed true to singleness. 



The authors find that their new results (given in tabular form 

 on p. 39, 40) fully confirm the view expressed in Report III that 

 doubles are only produced in the F 1 generation when both parents 

 throw doubles on self-fertilization. If only one of the parents is 

 found to yield doubles on self-fertilization, the other parent breeding 

 true to singleness, the F x generation consists entirely of Singles. 



The double-throwing Singles were crossed reciprocally with a 

 strain of pure Singles. The F x plants are all Single, but the F 2 from 

 these plants revealed a remarkable difference between the results 

 of reciprocal crosses, a feature which is not exactly paralleled by 

 any phenomena of inheritance hitherto observed. Where the pure 

 Single was used as mother, F 2 from each F x contained doubles, 

 whereas when the pure Single was the father, some of the F 2 fami- 

 lies contained doubles and some were all Singles. It follows that the 

 pollen grains of the double-throwing strains must be all, or nearly 

 all, bearers of doubleness; but that the egg-cells are of two kinds, 

 those that bear singleness and those that bear doubleness. 



The transmission of the cream-colour in the case of those Single 

 sulphur-whites which throw cream doubles follows a similar System, 

 the results of crosses indicating that the pollen-grains of these plants 

 are all, or nearly all, bearers of the cream-colour, but the egg-cells 

 are of two kinds, those which bear cream-colour and those which 

 bear whiteness. In this race an interdependence exists between 

 doubleness and the character of the plastid-colour, which however 

 has not yet been completely analysed. 



Poultry (p. 18—34). 



Comb Characters. In the previous report reasons were given 

 for regarding the rose-comb as in reality a Single comb modified 



