— 63 — 



soine cases the end cells of the prothallium divided also 

 longitudinalhy. The comparative size and form of a prothallium 

 grown under these conditions and one grown in light at the 

 normal temperature is shown in Fig. 59 and 61. Experiments 

 of a similar nature were also carried out for Alcophila 

 Loddigesii. These experiments are interesting in that they 

 show how Borodin and Schmidt, and Göppert and Schelting 

 could have obtained such contradicting results. 



d. EQUISETUM SPORES. 



There are no contradicting views in regard to the germi- 

 nation of Equisetum spores, both investigations cited admitting 

 and establishing the fact that germination occurred in perfect 

 darkness. I have repeated these experiments for spores of 

 Equisetum arvense, with the same result. It can then be 

 stated with absolute certainty, that Equisetum spores are 

 able to germinate under ordinary conditions of nourishment 

 and at a temperature of 19— 21° C, in darkness as well as in 

 light. From the foregoing results it seems that light or organic 

 nourishment is one of the necessary conditions for the germi- 

 nation of moss and liverwort spores, in order that chemical 

 changes may take place which will bring the reserve food 

 material into a condition in which it can be used in growth. 

 For the ferns, these chemical processes may be initiated 

 either by light or a sufficiently high temperature, while in 

 the case of Equisetum these changes can occur at a much 

 lower temperature in both light and darkness. 



4. SUMMABY. 



The more important results of the foregoing investigations 

 may be stated as follows: — 



1. Under ordinary conditions of temperature and in- 

 organic nourishment, moss and liverwort spores are unable to 

 germinate in the dark. Spores when subjected to only the 

 more strongly refrangible rays of the spectrum, behave the 

 same as in darkness. 



2. Organic nourishment in the form of either peptone 



