42 BOTANICAL GAZETTE [JULY 
for fern spores by Borodin.3?7 That is, the blue rays, the more 
strongly refrangible, have apparently the same effect as complete 
darkness. In the potassium bichromate light germination 
occurred after six or seven days, and with every evidence of as 
vigorous growth as under normal illumination. 
The effect of temperature on the germination of Marchantia 
spores in the dark was also investigated. A series of cultures 
was made for 32°, 29°, 27°, 24°, and 23° C., and all placed in 
the dark. After two weeks’ time they were observed, and ncne 
of the spores had germinated. They were then placed in the 
light to see if they had remained capable of germination. In the 
cultures which had been kept at 29° and 32° C. germination was 
retarded for a few days, but the spores from the remainder of the 
cultures grew after the usual length of time. 
The length of time required for germination, and the condi- 
tion of the material, rendered the preparation of sterile cultures 
impossible, so that the cultures with grape sugar were not very 
satisfactory. Although I did not succeed in bringing the spores 
to germinate under these conditions, they gave every indication 
of growth, and I attribute the failure to germinate only to the 
inroads of bacteria. Inthe dark in sugar solution the spores 
increased to three or four times their original diameter and 
formed large starch masses the same as in the moss proto- 
nemata. 
Further than this they could not be brought, although 
repeated attempts were made, and when the cultures were placed 
in the light even then germination did not proceed, showing that 
the spores had not remained capable of germination. If, how- _ 
ever, the cultures could have been kept sterile, there was every — 
indication that the spores would have germinated. 
3. FERN SPORES. 
A culture of the spores of Ceratopteris thalictroides was kept : 
in the dark for three months without any signs of germination, : 
while a sowing of the same spores germinated in the light after — 
% [bid., 536. 
