E. R. Saunders 363 



of seeds producing doubles is that in cases where sowings are made 

 from seed which has been kept for some seasons, a certain error is 

 likely to be introduced in the direction of making the proportion of 

 doubles appear greater than it actually is, the variations frf)m the 

 theoretical result in the case of old sowings being always in the same 

 direction. The fact that this increase in the proportion of doubles may 

 be obtained from a sample of quite good seed, after it has been kept, 

 shows that it cannot be attributed to a particular distribution of the 

 double-carrying ovules in different regions of the pod, such e.g. as that 

 those occurring in the distal region give rise to fewer doubles than those 

 occurring in the basal part, since in the case of Stocks all or nearly all 

 the ovules in each pod are naturally fertilised under favourable condi- 

 tions; hence a sample of loose seed is likely to represent all regions 

 equally. Moreover, direct experiment by means of halving the pods 

 transversely and sowing the seeds from the upper and lower halves 

 separately gave no indication of any such unequal distribution. 



Subjoined are some of the more striking instances in which the 

 greater viability of the seeds which give rise to doubles is plainly 

 manifest. 



i. In 1904 a glabrous dark purple plant gave a family of 11 single 

 and 5 double. This excess of singles was probably accidental since the 

 plant appears to have been a true eversporting individual, and no doubt 

 with a larger sowing would have given the usual preponderance of 

 doubles. 



In 1908 about 400 seeds from 9 of the F^^ singles were sown : 44 

 germinated of which 35 lived to flower, 8 being single and 27 double. 

 The families were composed as follows : 



The seeds from the 5 other Fi plants gave no result. 



In 1909, 30 seeds from one of the F^ singles were sown, only 

 1 germinated and this proved to be a double. 



In 1910, > 130 seeds from another F^ single were sown ; 21 germi- 

 nated, all of which lived to flower ; 7 were single and 14 double. 



ii In 1907 a glabrous white plant yielded an F^ of 83 singles and 

 100 doubles. 



