14 JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



forms and partly in very unequal numbers, 

 and co-ordinated we find : 



When these are collected 



38 plants with the sign 

 35 

 28 

 30 

 65 

 68 

 60 

 67 

 138 



AB 

 Ab 

 aB 

 ab 

 ABb 

 aBb 

 AaB 

 Aab 

 AaBb 



The whole of the forms may be classed into three essentially 

 different groups. The first embraces those with the signs AB, Ab, aB, 

 and ab : they possess only constant characters and do not vary again in 

 the next generation. Each of these forms is represented on the average 

 thirty-three times. The second group embraces the signs ABb, aBb, 

 AaB, Aab : these are constant in one character and hybrid in another, 

 and vary in the next generation only as regards the hybrid character. 

 Each of these appears on an average sixty-five times. The form AaBb 

 occurs 138 times : it is hybrid in both characters, and behaves exactly as 

 do the hybrids from which it is derived. 



If the numbers in which the forms of these sections appear be 

 compared, the ratios of 1, 2, 4 are unmistakably evident. The numbers 

 32, 65, 138 present very favourable approximations to the ratio numbers 

 of 33, 66, 132. 



The developmental series consists, therefore, of nine classes, of which 

 four appear therein always once and are constant in both characters ; the 

 forms AB, ab resemble the parental forms, the two others present 

 combinations between the conjoined characters A, a, B, b, which com- 

 binations are likewise possibly constant. Four classes appear always 

 twice, and are constant in one character and hybrid in the other. One 

 class appears four times, and is hybrid in both characters. Consequently 

 the offspring of the hybrids, if two kinds of differentiating characters 

 ar6 combined therein, are developed according to the formula 



AB + Ab-f aB-f ab + 2 ABb + 2 aBb -|- 2 AaB 2 Aab + 4 AaBb. 



This developmental series is incontestably a combination series in which 

 the two developmental series for the characters A and a, B and b, are com- 

 bined. We arrive at the full number of the classes of the series by the 

 combination of the formulse : 



A + 2 Aa-f a 

 B + 2Bb-fb. 



Second Trial. — ABC, seed parents ; 



A, form round ; 



B, albumen vellow 



abc, pollen parents ; 



a, form angular ; 



b, albumen green ; 



C, seed-coat grey-brown, c, seed-coat white. 



This trial was made in precisely the same way as the previous one. 

 Among ail the trials it demanded the most time and trouble. From 24 

 hybrids 687 seeds were obtained in all : these were all either spotted, grey- 



