Ig1g} STOUT—INTERSEX ES 125 
hybridization, and from that sterility ascribed to replacement of 
sexual reproduction by asexual means (GATES and GOODSPEED 9), 
in both of which the tendency is to give a very uniform impotence 
of both sexes. A high degree of impotence is’ present. in many 
plants regarded as pure species. JEFFREY (14, 15, 16) has recently 
emphasized the view that such sterility is to be considered as 
conclusive evidence of hybrid origin. Intersexuality, however, 
involves much impotence, and may very clearly develop in pure 
species through lability of the processes of sex determination. 
At this point one may well inquire whether differences in sex- 
uality somewhat akin to intersexuality may be present in species 
that. are morphologically fully hermaphrodite, and in which no 
appreciable impotence of sex organs is in evidence. For example, 
DARWIN reports that plants of “the short-styled form of Primula 
veris produce more seed than the long-styled in the proportion of 
nearly four to three (7, p. 19), and that in Lythrum Salicaria (6, 7) 
the mid-styled form is potentially capable of higher seed pyoduc- 
tion than plants or either of the other two forms. Judged on the 
basis of seed production, certain forms in heterostyled species 
appear to be more female than others. Sexuality of species as 
such is obviously more intense in some than in others if we are 
_to judge by seed reproduction. Much variation in total seed 
production is seen among races and among individuals of a race. 
Such considerations raise many questions regarding the determina- 
' tion of potentiality of sex reproduction through production of 
seed, and most especially of the relations of vegetative to repro- 
ductive function. Undoubtedly much variation in maleness and 
femaleness exists in sex organs that are morphologically perfect. 
The sexual behavior of female pigeons has especially been studied 
by Rrppte as an index of the degree to which femaleness is devel- 
oped. He states (22, p. 341) that “females hatched from eggs 
laid earlier in the season are more masculine in their sex behavior 
than are their own full sisters hatched later in the season. And 
several grades of females can be thus seriated according to season of 
hatching.”’ 
The existence of physiological incompatibilities (StouT 25) 
between sex organs that are fully formed, potentially functional, 
