396 
MABEL MARY BROWN 
one or the other sex growing independently, and did not know whether 
they had originated from the same or from different spores. The Marchals 
(191 1), as pointed out on a preceding page, conclude that F. hygrometrica 
is monoecious, but they do not describe their experiments. 
The gametophores remain for some time unbranched and sterile (fig. 9). 
The first branches observed arose from the basal part of the main axis 
(fig. 10) ; in such a case it is often difficult to determine which is the primary 
axis and which the branch. 
The branches resemble the main axis in every detail except that they 
are usually shorter. The basal part of the branch is enlarged and bulbous, 
like the basal part of the main axis. The cell walls of the lower part of the 
stem and of the branch are impregnated with a brown pigment similar to 
that in the cell walls of the rhizoids. Rhizoids and protonemata arise from 
the lower parts of both structures. The connection between the branch 
and the main axis is very loose, and when separated from the axis the inno- 
vation may be taken for a separate plant. This condition is probably 
responsible for the statement often made that F. hygrometrica is dioecious, 
the archegonia being borne on shorter stalks than those which bear the 
antheridia. 
The cultures were examined daily in order to note the first appearance 
of sex organs. In every case antheridia were developed before archegonia. 
In the greater number of the cultures, antheridia were observed from one 
month to six weeks after the appearance of the gametophores. However, 
in a few cultures they were not seen until six or eight months after the de- 
velopment of leafy axes. 
In culture 26, which is typical of the majority of the cultures in the series 
from 18 to 204, the spores were sown December i, 19 16, transferred to soil 
December 11, gametophores were noted February 10, and antheridia April 
13, 191 7. There were several deviations from this program in this series; 
for example, in culture 29, the history of events is identical with that of 
culture 26 until the time of the observation of the antheridia, which were 
first noted December 5, 19 17, almost a year from the time of the germination 
of the spore. In cultures numbered 20, 98, 106, 108, 109, 117, 118, 121, 
I37> I55» 158, 160, 163, 171, 172, 173, 175, 178, and 182, antheridia were 
not observed until the latter part of July and the first of August, 191 7, about 
seven months after germination. This difference in the time of production 
of antheridia in this series can not be attributed to the different soils upon 
which the cultures were grown, because the difference in the soils used does 
not correspond with the differences in the history of the cultures. In the 
series 208 to 234, 235 to 275, 276 to 302, and 303 to 328, there were no 
noteworthy differences in the history of the development of antheridia. 
The antheridial inflorescences may be recognized with the naked eye. 
The leaves surrounding the group of sex organs are so arranged as to give 
the head a discoid form (fig. 15). From twenty to thirty antheridia are 
borne in each group. 
