OCCURRENCE AND INHERITANCE OF SEX INTERGRADATION IN PLANTS 25 
Further, as the classification shows, a great many plants exhibit gradations 
between maleness and femaleness and hermaphroditism because of the more 
or less nearly complete degeneration or modification of parts. A female 
may arise from a hermaphrodite through the more or less complete suppres- 
sion or degeneration of stamens. Likewise a monoecious individual may 
become female by the degeneration or the entire suppression of the stamens. 
A male may arise from either one of such forms by the disappearance or 
more or less nearly complete degeneration of the carpels. When in a group 
of hermaphrodites the stamens of some of the plants are suppressed or de- 
generated we have a condition of gynodioecism, if the carpels are suppressed 
or degenerate a condition of androdioecism. When only parts of the plants 
exhibit the phenomena described we find a multiplicity of combinations. 
A gynomonoecious individual may arise from a hermaphrodite in which 
female flowers appear through the suppression or degeneration of the 
stamens. An andromonoecious individual may arise from a hermaphro- 
dite through the suppression or degeneration of some of the carpels. Gyno- 
monoecism and andromonoecism, just as well as gynodioecism and andro- 
dioecism, may appear in various gradations; in the former instance by virtue 
of the suppression or degeneration of larger or smaller numbers of parts of 
the plant, and in the latter case because of changes that may occur in larger 
or smaller numbers of individuals in a group of plants. 
The appearance of sporadic female or male flowers on a hermaphro- 
ditic plant may bring about a condition* of gynomonoecism or andro- 
monoecism without necessitating the degeneration of parts. Thus, also, 
among dioecious forms the appearance of male flowers on the pistillate 
plants or of female flowers on the staminate plants gives all possible sex 
combinations found in plants. 
There is still another form in which a so-called polygamous condition 
may exist. In these cases either the female or male elements, although 
morphologically perfect, are physiologically, either one or both, function- 
less. We find also gradations in the degree of sterility of stamens or ovaries 
of parts of the plant, of the whole plant, or of varying numbers of individuals 
in a group of plants. 
Earlier investigators who have observed pistillody of the stamens, 
staminody of the pistils, the appearance of male flowers on female plants, 
etc., considered them monstrosities and grouped them as such. Moquin- 
Tandon (1841) and Masters (1869) include all such phenomena under 
teratology. The many cases of this sort reported for plants would suggest 
that this treatment is by no means adequate. 
Wehrli (1892), who reports on a case of the complete transformation of 
a male catkin of Coryllus aiellana L., has brought together all the available 
literature from 1741 to 1892. He lists over 80 distinct species, monoecious, 
dioecious, and hermaphroditic, in which such modifications of floral parts 
have occurred. The phenomena he observed include: the appearance of 
