236 NATURAL HISTORY BULLETIN. 



smoke. This so-called smoking takes place at intervals and 

 seems to be brought about by any slight disturbance in the 

 atmosphere; the breath often being sufficient to cause the 

 ejection of thousands of spores. This phenomenon is well 

 known to all those who are familiar with the plants of this 

 group, but the cause is not so well known. Since the puffing 

 of the spores takes place after removing the bell jar, it is 

 thought by some students of fungi that the ejection of the 

 spores is due to the contraction of the ascus in- drying. This 

 is not the case for if uninjured asci from fresh plants be 

 placed on a slide in water, thus preventing every possibility 

 of drying, the ejection will take place and may be easily 

 studied with the microscope. The addition of water does 

 not hinder the processs and the activity of the apparatus is 

 even stimulated in this way. 



The ejection of the spores probably takes place continually 

 while the plants are under cover but the ejection of the spores 

 in large numbers at the moment of raising the bell jar is 

 probably due to the sudden change in the atmospheric 

 pressure. The bursting of the ascus is brought about by the 

 internal pressure resulting from the process of endosmosis. 

 The ejection of the spores does not take place if the asci are 

 immersed in a solution of alcohol or glycerine, showing that 

 those agencies which tend to promote the process of endomosis 

 stimulate the spore-dispersal. 



If asci immersed in water are carefully studied during the 

 process of spore ejection, they will be seen not to contract, but 

 to expand just before the ejection of the spores and then to 

 assume their normal form except for the rupture at their free 

 end, and to remain thus if unmolested. If several asci from 

 fresh plants of Lachnea scutellata (Linn.) Sacc, PI. VI, Fig. 

 1, in which the spores are arranged in a definite row in the 

 ascus, be studied as described above, the spores will be seen 

 to crowd toward its free end so that the row is broken up and 

 the spores are crowded together, the ascus becoming very 

 much expanded at that point. They remain in this position 



