;^8 



THE PURE LINE HYPOTHESIS. 



In the majority of the famihes both red and non-red off- 

 spring were obtained, as would be expected. The single non-red 

 hybrid (XIV.) only produced non-red offspring, and it would 

 appear that the plant was incapable of producing red oft'spring. 

 All the remaining parents were red. Altogether the red parents 

 produced 141 red offspring and 35 non-red, and these figures are 

 divergent from the 3 : i (132 : 44) ratio. It is very probable that 

 the red parents which did not produce non-red offspring were 

 incapable of so doing owing to the absence of an inhibitor, and 

 if the individuals of such 'families, amounting to 31 in number, 

 are removed from the series we obtain the ratio no: 3s, which is 

 close to the familiar one. 



In the right hand column of the table the mean colouration 

 of the red members of the different families is given. It will be 

 seen that, as in the case of the variegation of the leaves, the 

 means of the different families vary considerably, whereas 

 according to the pure-line hypothesis the means should tend to 

 remain stationary with such self-fertilised families. 



In the next table the parents and their respective ifamilies 

 are arranged in four groups in such a manner that the means of 

 the groups of parents fall by alwut 15 per cent., as we pass from 

 one group to the next, and it is desired to compare these means 

 with the means of the groups of families in order to ascertain 

 whether there is any corresponding reduction. 



