May, 1923] VALLEAU — INHERITANCE IN THE STRAWBERRY 
269 
progeny of only a single cross of this type has been studied. The female 
parent used was a pistillate derived from crossing a wild pistillate F. vir- 
giniana (FM) by the hermaphrodite 778 (. HH) (5/15, table 3). All pistillates 
from such a cross should have the constitution FH. This female was 
crossed with a wild F. virginiana staminate. Twenty Fi seedlings were 
obtained. Eleven of these were pistillate and 9 hermaphrodites or somatic 
hermaphrodites, thus giving a close approximation to the expected 1 : 1 
ratio. The pistillates were all very fertile. Of the 9 hermaphrodites 
obtained, 3 set no fruit while 6 set fruit in varying amounts, from only a 
nubbin on the primary flower with the others sterile, to some which set 
fruit on flowers of all degrees but with a portion of the tertiaries and quater¬ 
naries sterile. If the 9 hermaphrodites are divided into two groups with 
regard to whether sterile flowers or fertile flowers predominate, there will 
be 6 classed as sterile and 3 as fertile. These plants are all of the constitu¬ 
tion MH, the H factors all being identical and the M factors being derived 
from the wild male parent. Thus the male factor of the wild female was 
replaced by an hermaphrodite factor in the female parent of this cross, and 
maleness was introduced into the progeny by a wild male (MM). The 
results of this cross are similar with respect to fertility of the hermaphrodites 
to those obtained from cross 5/15 in which a wild female (FM) was crossed 
with a cultivated hermaphrodite (F[H). It is thus seen that maleness may 
be introduced into otherwise fertile strains of strawberry by the use of 
either the wild females or the wild males. Even though the flower types 
with respect to fertility of the hermaphrodites are not always clear-cut, 
these results are in accord with the chromosome theory of sex inheritance. 
It would seem that the outward expression of a given sex determiner may 
be influenced by the sex determiner with which it is associated and also by 
the autosomes associated with the sex chromosomes in the nucleus. 
Discussion 
The Sex Determiners 
In the above presentation of data, and in the conclusions which have 
been drawn from them, it has been assumed that the determiners for sex 
are definite factors and that they are carried in a definite pair of sex chromo¬ 
somes. We must assume that the various sex conditions which appear 
have been derived originally from an hermaphroditic condition in which 
the determiners for the two sexes are linked in each of a pair of chromosomes. 
The various sex types which appear in either the grape or the strawberry, 
or, in fact, in any of the flowering plants which are dioecious and show a 
variety of sex types intermediate between staminate and pistillate, we 
assume to have been derived by suppression, either partial or complete, of 
one of the determiners for sex in the sex chromosomes, leaving the other 
factor functional (5). It can hardly be assumed that one or the other sex 
