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with their normal vigor, either in light or darkness; the 

 growth was however more lnxuriant tban in the cultures 

 which were supplied with more peptone. 



b. MARCHANTIA SPORES. 



The work of Leitgeb lipon the effect of light on the 

 germination of liverwort spores has already been mentioned. 

 Since he found that the spores were unable to germinate in 

 complete darkness, a confirmation of his resnlts at this point 

 can not be withoiit interest. A ciüture 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 

 resnlts in regard to the intensity of light necessary for 

 germination. In weak light germination was retarded , and 

 when growth did take place, the spores prodnced only a 

 narrow filament with a small amonnt 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 for fern spores by Borodin. 1 That is, the blue 

 rays, the more strongly refrangible, have apparently the same 

 effect as complete darkness. In the potassium dichromate 

 light germination occurred after six or seven days, and with 

 every evidence of as vigorous growth as under normal 

 illuminatioD. 



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 investigated and 

 none of the spores had germinated. They were then placed 

 in the light to see if they had remained capable of germination. 



1 C. c. p. 536. 



