1898 | THE GERMINATION OF FERN AND MOSS SPORES 41 
to state with certainty. Some cultures which were grown in the 
dark in an inverted position showed that the protonemal 
branches grew downward, away from the culture medium. These 
experiments would tend to show that the vertical growth was 
not due to geotropic sensitiveness, but rather perhaps to nega- 
tive hydrotropism, as in the case of fungi. More experiments 
in this line are necessary, however, to make these conclusions 
certain. 
It was thought that by using the culture medium with less 
peptone the protonemata might be brought to a more vigorous 
development. A second series of experiments was carried out, 
in which the same culture medium as described above was used, 
except that only traces of peptone were added. Even in this 
‘medium the protonemata did not grow with their normal vigor, 
either in light or darkness. The growth was, however, more 
luxuriant than in the cultures which were supplied with more 
peptone. 
2. MARCHANTIA SPORES, 
The work of Leitgeb upon the effect of light on the germi- 
nation of liverwort spores has already been mentioned. Since 
he found that the spores were unable to germinate in complete 
darkness, a confirmation of his results at this point cannot be 
without interest. A culture of Marchantia spores was kept in 
the dark for over two months without any signs of germination. 
At the end of this time they were placed in the light, and after 
a lapse of six days the majority of the spores had germinated. 
My experiments also confirmed his results in regard to the 
intensity of light necessary for germination. In weak light ger- 
mination was retarded, and when growth did take place the 
Spores produced only a narrow filament, with a small amount of 
chlorophyll. The filament did not attain any considerable size 
or form a germ disk. 
As regards the part of the spectrum effective in producing 
germination, my experiments with Marchantia spores yielded the 
Same results as for moss spores, and the same as has been found 
