586 On the Inheritance of Heterostylism in Primula. 
while the rest are not. This fact suggested that there may be a differentia- 
tion between egg-cells of the same plant, such that some are capable of 
illegitimate fertilisation, others incapable. 
To test this possibility, we made a large number of trials with P. acaulis 
and sinensis, pollinating some flowers legitimately, some illegitimately, and 
others with pollen of both types. We anticipated that the double pollina- 
tions, in which pollen of both types was put on the same stigma, would 
produce a maximum number of seeds. In the case of P. stnensis, by making 
use of the fact that green stem and pinnate leaf are recessive to red stem and 
palmate leaf, it was possible to arrange these double pollinations in such a 
way that the paternity of each resulting seedling would be apparent, and 
thus the number of individuals derived from each set of pollen grains could 
be ascertained. 
This series of experiments has, however, led to no definite conclusion. 
They were carried out through two seasons, and an enormous number of 
fertilisations were made, but the resulting figures were so discrepant that we 
are unable to give either a positive or a negative answer to the question 
proposed. These discrepancies are partly due to great individual differences 
between plants and between flowers of the same plant, but in all probability 
serious irregularities were also introduced in the actual operations owing to 
the difficulty of applying the two sorts of pollen equally to the same stigma 
under really uniform conditions. If these technical difficulties could be 
overcome, a valuable result might possibly follow from the experiment. 
