tor9] STOUT—INTERSEX ES 127 
capable of fusion when juxtaposed. It may consist of (1) the 
more or less immediate modification of physical structure of the 
cells (in spermatogenesis and oogenesis) that are to fuse, and 
(2) of modifications of organs associated with the development 
of sex cells, either in the sporophyte or the gametophyte, or both. 
All of these latter are in reality secondary sex characters; true 
primary sex characters are to be considered as belonging to the 
cells that fuse, a view clearly stated by STRASBURGER (26). 
The relationship between morphological and physiological sex 
differentiation is well shown in the flowering plants. We may 
take a hermaphrodite with perfect flowers as a type. Primarily 
such a plant is:a spore-producing individual; it is a sporophyte 
in which heterospory is in evidence. The stamens bear micro- 
spores, the pistils bear macrospores. These spores are asexual 
in that they are not able to fuse. They are sexual, however, to 
the extent that sex is here already determined. Anatomical 
expression of maleness and femaleness here appears in sporophytic 
structures, and the particular sex of the future generations of 
cells in asexual descent is predetermined until the next fusion of 
sex cells or the development of a sporophyte through apogamy. 
The pollen grains grow into microgametophytes producing male 
sex cells or sperms. The macrospores grow into the macro- 
gametophytes which produce the eggs. The alternation of gen- 
erations is marked; the one is sporophytic; the other is 
gametophytic. But maleness can be traced back through the 
pollen tube, through pollen, beyond reduction divisions, to the be- 
ginning of somatic differentiation of stamens. Likewise femaleness 
can be traced to the beginning of the organogenesis of the pistil. 
These facts certainly justify the application of the terms male and 
female to structures that in their morphology are sporophytic. 
This view has frequently been criticized by those who emphasize 
the morphology of the alternation of generations (MACMILLAN 20). 
Furthermore, it is to be noted that in the greater number of ani- 
mals the gametophytic generation is omitted or perhaps to be con- 
sidered as reduced to a single cell generation, and that here the 
conditions of maleness and femaleness are most essentially proper- 
ties of individuals and structures that are wholly sporophytic. 
