INHERITANCE OF SEX IN MERCURIALIS ANNUA 42 1 
which had produced no seeds, was polHnated by one of the males secured 
from the Brooklyn Botanic Garden. Several hundred of seeds were 
collected. These were later germinated and gave approximately a one-to- 
one ratio of males and females. 167 males from this parentage were potted 
and grown in the propagating house of the New York Botanical Garden. 
One plant produced 2 seeds, seven months after germination. The rest of 
the plants continued to grow vigorously, producing an abundance of male 
flowers. Some of the males lived twelve months. The 2 seeds failed to 
germinate. 
It was quite evident that the growing of males under greenhouse con- 
ditions was not favorable for the production of seeds. Out of a total of 
215 males only 4 had produced seeds, giving a total of 17 seeds. From these 
17 seeds one male plant was secured. The remaining failed to germinate 
and 3 seeds were lost. The first two males set seeds when they were ten 
months old. After that there was a rapid decline of vegetative vigor fol- 
lowed by death. The third male reported as bearing seed did so three 
months after germination. It is to be noted that the vegetative vigor of 
that plant was greatly reduced. The fourth case was one in which the 
male plant produced seeds at the end of seven months, and it continued to 
grow until it was twelve months old. 
In the spring of 19 15 seeds were sown out of doors in the experimental 
plot of the New York Botanical Garden, with a view of watching the male 
plants throughout the growing season. As soon as the sex of the seedlings 
was apparent, the females were removed and the males permitted to de- 
velop to the maximum. The seedlings were up in May. The plants were 
examined at almost daily intervals. They made a very vigorous growth, 
producing countless numbers of male flowers. 
The first appearance of female flowers was noticed on the first of August 
on plant no. 247. The flowers were in various stages of development. 
During the month of August, 16 other plants produced female flowers and 
seeds. The relation of male and female elements described for my female 
cultures does not hold for the male. When the female flowers began to 
appear, they occurred usually singly among the numerous male flowers on 
the branches that bore them. As noted before, the female ovary normally 
is two-celled, producing a two-seeded fruit. Occasionally the female 
flower on the male plant is one-celled, one carpel only being developed. 
In the case of the appearance of this condition in the male plant, the missing 
carpel is not replaced by stamens as is the case when there is a one-carpelled 
ovary on the female plant, shown in figure 3, page 412. In no instance have 
I found the female elements on the male plant accompanied by the varia- 
tions in the disposition of male and female elements which have been noted 
earlier for female plants and which are represented diagrammatically in 
the figures on page 412. Upon the male as well as upon the female plant 
three-seeded fruits (fig. B) are found. The female flowers found on a male 
