132 THE MENDEL JOURNAL 



Now, as we have already pointed out, the in- 

 dividuals of Bryonia alba are hermaphrodite, bearing 

 both male and female flowers. In other words, as 

 individuals they are not differentiated with regard 

 to sex. We here meet with a new kind of cross, 

 different from that between the unisexual individuals 

 of B. dioica. When the unisexual individuals of 

 this latter species are crossed with each other, we 

 are really dealing with the crosses of two differentiated 

 individuals, in each of which the one sex has segregated 

 from the other. But in the cross of B. dioica with B. 

 alba we are dealing with one where a sexually 

 differentiated individual is crossed with an un- 

 differentiated one. The results show that we may 

 regard differentiation and non-differentiation (absence 

 of differentiation) as definite characters capable of 

 hereditary transmission. Hence we are here dealing 

 with a cross between a differentiated unisexual plant 

 and a non-differentiated hermaphrodite one, the 

 unisexual character being apparently dominant. 



Let us first consider case No. 2 in the table above. 

 Some of the pollen-cells of the male flower of B. dioica 

 are carrying maleness and others are carrying female- 

 ness. The ego-cells of the female flowers of B. alba 

 are carrying undifferentiated hermaphroditism. In 

 a cross of the kind we are considering, two 

 results may happen. For both the male and female 

 carrying pollen-cells of B. dioica will meet the 

 egg-cells of B. alba carrying the hermaphroditic 

 character. In the former case there will be pro- 

 duced fertilised egg-cells bearing the characters of 



