1898 ] THE GERMINATION OF FERN AND MOSS SPORES 31 
already been stated, to the fact that the conditions of tempera- 
ture, light, etc., were such that certain chemical processes neces- 
sary for germination could not be active. The results with fern 
spores show that heat is able to effect this change as well as 
light, so that germination may be called forth in complete dark- 
ness by subjecting the spores to a higher degree of temperature 
than the normal room temperature. That moss spores would 
be affected in the same way as fern spores would seem quite 
probable, but nevertheless my experiments in this direction have 
failed to find any temperature at which moss spores will germi- 
nate in complete darkness, when supplied with only inorganic 
material. The temperature to which the general cultures were 
exposed ranged from 1rg—-21°C. Cultures were made for the 
following degrees of temperature: 23°, 24°, 27°, 29°, 32°, 
and 35° C., and in each case in complete darkness. The cul- 
tures at 35° C. were kept for four days. At the end of that 
time no signs of germination were visible, hence they were 
removed to the light and kept at the ordinary temperature. The 
failure of the spores to germinate under these conditions showed 
that they had been killed by the high temperature. The other 
cultures were allowed to remain in the dark for six days and 
then removed to the light. The spores subjected to 32° were 
not killed, but a very marked retardation of germination 
occurred, since the period required for germination was extended 
from three days to ten. The cultures that had been kept at 29° 
also showed a retardation of germination, five days being 
required after the exposure to light. In the other. three series 
of cultures at 27°, 24°, and 23°, no apparent retardation of 
germination was noticed when the spores were exposed to light. 
The above experiments have shown clearly that a contin- 
nous exposure to high temperatures is not sufficient to produce 
germination of the moss spores in the dark. As suggested by 
the results obtained by Liebenberg** for seeds of Poa, it was 
thought that perhaps a change of temperature might be effective 
in producing germination. To this end the following experi- 
*4 Bot. Centralblatt 14:21-26. 1884. 
