394 
MABEL MARY BROWN 
germinated. Many spores, however, failed to germinate even when left in 
the same situation before the window. From my observations it thus ap- 
pears that the condition of the spores, the culture medium used, and illumi- 
nation are factors affecting the length of time necessary for the germination 
of spores of F. hygrometrica. Since all the cultures were kept at room 
temperature, they furnish no information as to the effect of different tem- 
peratures on germination. 
After the rupture of the exospore and the beginning of the growth of the 
protonema (fig. 3Z>), or even at the same time, a rhizoid may develop and 
grow out from the spore or from the basal cell of the protonema in the 
opposite direction to that of the protonemal filament. 
Rhizoids are commonly distinguished from protonemata by their oblique 
septa, and by the presence of a brown pigment in the cell walls. An exam- 
ination of the rhizoids shows that chloroplasts may be present in their cells, 
but not in so large numbers as in the protonemal cells; the septa may be 
almost perpendicular to the long axis of the rhizoid cells as is the case in 
protonemata; and the brown color may be almost entirely lacking. These 
latter conditions are often found in rhizoids arising from the spore and the 
protonema, as well as in those originating by regeneration from the vege- 
tative parts of the gametophore and from the sex organs. 
It was found that protonemata branch profusely in culture solutions, 
but that gametophoric buds are very seldom formed on protonemata 
growing in such solutions, although some such cultures were kept from the 
middle of November until the first week in April. On the other hand, 
protonemata transferred from these cultures to pots of soil produced leafy 
axes, on an average, in eight weeks. It might appear that some substance 
necessary for gametophore development is present in the soil but absent 
from the culture solution ; but since protonemata may be kept in an appar- 
ently healthy condition in Marchal's solution for long periods of time, and 
since gametophores are formed on protonemata growing on filter paper 
soaked in Marchal's solution, this explanation does not seem adequate. 
It is possible that the stimulus supplied by the presence of a solid substratum 
is necessary for the formation of leafy axes, or that if the protonemata had 
been kept longer in the culture solution such axes would have been formed. 
The Distribution of Sexual Characters 
After the transfer of the individual protonemata to separate pots of 
soil, growth takes place for some time. An area varying from one to five or 
six square centimeters on the surface of the soil in each pot is covered by a 
green felt-like growth at the expiration of a period of five to six weeks after 
the transfer. In every case this growth originated from a single spore. 
Gametophores do not develop on any of the cultures within a shorter 
period of time than five weeks after the protonemata are transferred to the 
