26 
CECIL YAMPOLSKY 
male flowers on female plants, of pistils and stamens in the same catkins, 
appearance of perfect flowers on male plants, abortion of stamens, pistillody 
of stamens, staminody of pistils, yearly changes in flowers on a tree (nut- 
meg), sectorial arrangement of male and female inflorescences in Pinus alba, 
and many more. Wehrli's references and resume are so complete that they 
have not been repeated here. However, a number of typical examples will 
be listed from the literature since Wehrli's paper. 
Haring (1894) gives an elaborate series of drawings showing various 
gradations in the transition stages of stamens into pistils and of pistils into 
stamens in Salix caprea L. and S. cinerea L. He observes that his work 
shows the tendency in willows to the greatest plasticity in the structure, 
form, and sex of the floral organs, including the growing together or the 
separation of parts, the replacement of one sex organ by that of the 
opposite sex, and the transition of one sex into the other. The author goes 
on to say that the phenomena that he has described show the morphological 
equivalence of the organs of both sexes, in the position of the sex organs 
no matter whether male or female, in the replacement of the organs of one 
sex by those of the other, and in the transition of one sex into the other. 
In the plant kingdom not only is there a transformation of one sex organ 
into the opposite but the transmuted organs are quite regularly functional, 
though sterility of the intergrade organs is not uncommon. Intergradation 
of sex in plants, if measured in percentages, may be from a fraction of one 
percent to one hundred percent, in the former case by the pistillody of a 
single stamen or staminody of a single pistil on a whole plant and in the 
latter case through the complete alteration of a male plant into a female. 
Sex intergradation as evidenced by the appearance of one or more parts of 
the opposite sex on a given plant does not seem to affect the fertility of 
the plant. 
We may note in more detail some of the most carefully studied forms 
which show these sex intergrades. Satureja hortensis is described by Cor- 
rens (1904) as occurring in three forms: (i) plants with female flowers; (2) 
plants with hermaphroditic flowers, hermaphroditic flowers with shriveled 
anthers, and female flowers; (3) plants with hermaphroditic flowers and 
shriveled anthers, and female flowers. These shriveled anthers indicate a 
tendency to abortion or infertility of the organs of one or the other sex, 
paralleling the conditions in Goldschmidt's sex intergrades. 
Dimorphotheca pluvialis is trimorphic (Correns, 1913). In an earlier 
paper (1906) he describes the ray flowers as female, the outer disc flowers as 
hermaphroditic, and the innermost as male. 
Correns (1904) finds five forms of Silene inflata: males, females, her- 
maphrodites, gynomonoecious, and gynodioecious individuals. 
Wittrock (1886) describes five different kinds of inflorescences in Acer 
platanoides : (i) individuals exclusively female, (2) individuals whose first 
flowers are female and their later flowers male, (3) individuals whose first 
