330 T. H. Morgan 
was very marked. It was equally well seen in the rare hermaphro- 
ditic flowers that contained both antheridia and anthegonia. 
In a very small number of cases the flowers were exclusively female. 
Experiments were tried with the sporophytes of purely male 
flowers, mixed flowers and purely female flowers Protonemata 
were obtained from each and the sex of their flowers recorded. In 
all cases the result was the same as in the first generation, irre- 
spective of the kind of sporophyte utilized. Flowers of the three 
kinds appeared in all, the males in excess, even when a purely 
female flower had been used. Evidently the factors that deter- 
mine male and female flowers are not decisive for the kind of 
gametes they produce. ‘The results show clearly that the tissues 
of the sporophyte carry the conditions for both sexes, and that 
these become “separated”’ when the spores are formed. 
It is perhaps not without significance to observe that the male 
flowers appear some time before the female ones, although the 
protonema is bisexual as subsequent results show. If this early 
suppression should continue throughout life the result would be 
difficult to distinguish from a male plant. 
The Marchals point out that since the diploid or double number 
of chromosomes is present in all the cells of the sporophyte and the 
reduction occurs when the spores are formed, the “separation” 
of the sexes must occur also at this ttme. When we recall that in 
animals the “separation” of the sexes also occurs according to 
some current theories at the reduction period it becomes a matter 
of extraordinary interest to determine the meaning of this phenom- 
enon. No less striking is the fact that with half the number of 
chromosomes some of the spores are male producing, others female 
producing. ‘The product of the sexual union of the germ cells 
derived from these spores is a hermaphrodite. If we are justified 
in extending to animals the general point of view here reached, we 
might conclude that at the reduction period in the egg as well as 
in the sperm a “separation” of the male and the female factors 
takes place. If we assume that it is a matter of “chance’’ whether 
the egg or its polar body become a male or a female, then selective 
fertilization follows, but even with this assumpaon it would still 
remain a puzzle what determines the sex of the resulting hybrid. 
