108 SCHAFFNER: SEXUAL STATE IN SAGITTARIA LATIFOLIA 
preted as being due to the presence or absence of a specific sex 
chromosome gene or set of genes. The sexual expression changes 
with the proper change of environment as has been abundantly 
shown by the writer and others through direct experiment. 
Therefore sexuality as maleness or femaleness is not primarily 
a matter of heredity. There can be no doubt that apparently 
the functional activity which leads to maleness or femaleness 
under the given environment or at the proper stage in the 
ontogeny may depend on the properties of a single chromosome 
in some groups, and in others on a number of chromosomes. 
But even with such chromosomes present it would still be possible 
to change the sexual state, since the influence of such hereditary 
factors must be the same in bringing about a given sexual state 
of the cell, whether neutral, male, or female, as any other in- 
fluence which affects the metabolic processes. As stated above, 
the writer has shown by observation and direct experiment in a 
considerable number of plants that the sexual expression of an 
individual or part of an individual as male, female, or hermaph- 
rodite, of various type and degree, is not at all due to a compelling 
sex factorial arrangement in the organism and that the same 
individual may at one time be pure male, at another time pure 
female, and at another hermaphroditic. The given sexual 
character can only be understood and explained by the circum- 
stances of its expression even though we believe that the ex- 
pression of a given sexual condition must come through an 
ultimate hereditary constitution which permits or leads up to 
that condition under the given environment. 
It is, therefore, entirely superficial and contrary to both 
observation and experimental evidence to treat sexual expres- 
sions and sexual characters as being dependent on three simple 
Mendelian factors and their combinations, namely, F, M, H, 
FM, FH, MH, or whatever such symbols are employed. The 
inadequacy of such a procedure becomes evident when one can 
cause all the characters, which are supposed to be due to such 
different factorial combinations, to be developed in a single 
individual. 
If one takes a comprehensive view of the plant kingdom 
certain fundamental facts become prominent. Sexuality in the 
lowest organisms is purely physiological. In the higher plants 
the segregation of chromosomes has nothing to do with the 
