SCHAFFNER: SEX REVERSAL IN THE JAPANESE HOP 77 
to be a matter of nuclear and chromosome morphology. The 
next steps are perhaps now possible—to ascertain something of 
the real nature of sexuality and a more definite knowledge of 
sex control in favorable plants. It appears to the writer that this 
must, to some extent at least, lead into the fields of ionization 
in chemistry and electrons and electricity in physics; in other 
words the biological phenomena of sex are probably funda- 
mentally physico-chemical and not morphological. 
CONCLUSION 
From the results of the experiments with Humulus japonicus 
and other plants, it is evident that dieciousness with its accomp- 
panying sexual dimorphism is not due to the absence in either 
the staminate or carpellate individual of a complete set of 
hereditary factors for the expression of all the sexual characters, 
both male and female; nor is the monosporangiateness of the 
normal individual due to the presence of a homozygous or 
heterozygous condition of any kind of hereditary sex determi- 
nation whatsoever, which might be assumed to gain or lose domi- 
inance at the time of the reversal of the sexual state; for, as 
shown in the preceding discussion, all of the staminate plants 
changed to a greater or less extent to femaleness and nearly 
half of the carpellate plants showed reversal to maleness by 
simply subjecting them to an unusual environment. 
Thosewho are seeking an explanation of sex in terms of homo- 
zygous and heterozygous conditions of the male and female indi- 
viduals are following a delusion obtained from an incomplete 
knowledge of the phenomena of sexuality as exhibited in the plant 
kingdom; foritisevident that gametophytesare haploid organisms 
and so cannot have their factors or chromosomes in a yoked condi- 
tion, yet males, females, and hermaphrodites, and reversals of the 
given sexual states occur side by side in homosporous plants, 
including liverworts, mosses, hornworts, ferns, lycopods, an 
horsetails. In heterosporous sporophytes, bisporangiate individ- 
uals including the monecious species are the rule, and the 
diecious species represent only specialized conditions in respect 
to the sexual state; so here also, although the organism is diploid, 
the dieciousness is not at all caused by homozygous and heterozy- 
gous factors or chromosomes which control the sexual state, 
since both’ individuals can be caused to change to the opposite 
