1893] THE GERMINATION OF FERN AND MOSS SPORES 35 
ness, with the same increase in size of the protonema as in the 
case where sugar alone was used. In the cultures with sugar 
nearly every spore germinated, both in light and in darkness; in 
the peptone culture in the light also the same, but in the dark 
the number of spores which germinated was relatively small. 
The above results had already been obtained when Goebel’s pre- 
liminary note” concerning the same phenomenon appeared. 
Similar experiments to the above were carried out for Bryum 
pendulum, Brachythectum rutabulum, and Mnium cuspidatum. With 
these species essentially the same results were obtained as regards 
the germination in light and darkness, but the protonemata 
showed no increase in size, which was such a noticeable feature 
in the case of the Funaria spores. In the peptone cultures the 
number of spores germinating in the dark was rather smaller 
than for Funaria. 
That the germination in the dark is due to the nutritive value 
of the sugar and peptone is highly probable, but still it might be 
claimed that osmotic pressure was the active agent. In order to 
- throw some light upon this point, the following experiments were 
carried out: Spores of Funaria hygrometrica, Bryum pendulum, and 
Brachythecium rutabulum were placed ‘in culture and supplied with 
a 0.5 per cent. solution. of KNO,. The cultures in the light 
showed germination after the usual length of time, but no sign 
of germination was observed in those which were deprived of 
light. Experiments with the same results were also carried out 
for the same species in a I per cent. solution of KNO,;. De 
Vries*7 has shown that the osmotic value of KNO, is about 
double that of grape sugar with equal parts of the gram-mole- 
cule, or more exactly, the isotonic coefficient of grape sugar is 
1.88. The osmotic value of a 0.5 per cent. solution of KNO,, 
Or approximately a 1 gram molecule solution, would be about the 
Same as that of a 2 per cent. grape sugar solution, or a 4 gram- 
molecule. The failure then of the spores to germinate under 
the above conditions would tend to show that the osmotic pres- 
*° Flora 82:75. 1896. ; 
*” Jahrbiicher fiir wiss. Bot. 14:454. 1884. 
