554 



THE PURE LINE HYPOTHESIS. 



In family XII., the so-called intermediates had flowers which 

 retained a general pale-yellowish tinge after immersion in alcohol. 

 Although such was the case, the flowers were very markedly 

 different from those in w^hich chromoplasts were typically pre- 

 sent, and they more nearly approached the flowers with chromo- 

 plasts " absent." 



On referring to the right-hand side of the table, it will be 

 seen that on adding together the offspring of the hybrids which 

 possessed chromoplasts, we obtain i6 plants with chromoplasts 

 absent and 50 with chromoplasts present. It will be noticed that 

 these numbers are close to the i : 3 ratio. Barring family XII., 

 all the hybrids which possessd no chromoplasts only produced 

 oft'spring in which chromo]>lasts w-ere absent. 



It is clear that a marked segregation occurs with respect to 

 this character ; but further breeding would be essential in order 

 to throw light on the nature of the factors involved. 



