SCHAFFNER: SEXUAL STATE IN SAGITTARIA LATIFOLIA 109 
sexual expression, the sex of the gametophyte coming through 
the process unchanged. Unisexual forms are plainly related by 
intergradations to the more primitive hermaphrodites. Sex is 
from the lowest to the highest expressed in three simple states, 
female or positive, male or negative, and neutral, but with 
numerous gradations of intensity and fixity between either 
extreme and the neutral condition. Sex is definitely reversible, 
in many cases at least, through environmental influence. Men- 
delian phenomena and unit factors are concerned with minute 
morphological and physiological characters of multitudinous 
diversity, ranging from the unicellular forms to the higher plants 
and the higher animals. The phenomena of sexuality are en- 
tirely different. The evolution of primary sexual dimorphism 
is attained, being practically complete, before the multicellular 
condition is reached. Secondary sexual characters of the lower 
forms are in no way different from those of the higher. The 
only difference is that in the higher the cell has a larger number 
of factors which may become dimorphic or trimorphic. It is 
only in a few plants and in the higher animals that there is a 
seeming similarity to Mendelian segregations, because of the 
sex ratios obtaining and because of a certain type of asscciation 
of specific chromosomes which it has become the vogue recently 
to call ‘‘sex chromosomes.’’ Such allosomes with peculiar dif- 
ferential complements of factors, which are not to be regarded 
as of any different nature from other factors in other chromo- 
somes, may and no doubt do in certain groups of organisms give 
the cell a functional activity that leads to a specific sexual state 
under the ordinary environment of the species and the ordinary 
hereditary complex. But the control is brought about in the 
same way as through any other environmental influences, like 
length of illumination period, external nutritive supply, etc., 
which are known to control or modify the sexual state in the 
individual. It is far better to call these special chromosomes 
“allosomes”’ in contradistinction to the “autosomes” as was 
done by Montgomery,* who proposed the terms, rather than 
“sex chromosomes.”’ The matter will thus be considerably 
cleared for a rational and understandable discussion of the prob- 
* MonTGomERY, Jr., THOS. H. The [Terminology of aberrant chromo- 
somes and their behavior in certain hemiptera. Science N. S. 23: 36-38. 
1906. 
