PUFFING IN THE DISCOMYCETES 



233 



libertiana), have succeeded in photographing it in the following 

 manner. Large numbers of sclerotia were germinated and, as soon 

 as the stipitate apothecia had attained full size, some scores of the 



Fig. 113. — Arrangement ot apparatus in preparation tor photographing a cloud of 

 spores liberated during the puffing of the apotliecia of Sclerotlnia sclerotiorum 

 (= S. libertiana). An inverted glass dish, 6 inches wide, on the table, covers a 

 number of stipitate apothecia developed from sclerotia. Bright sunlight falls on 

 the fruit-bodies, and behind them is a black back-ground. A pliotographic 

 camera (not here shown) is focussed on the centre of the dish. By means of 

 suitable screens, the air around the dish is kept as still as possible. When the 

 dish was raised a cloud of spores was emitted, as shown in the next illustration. 

 Photographed by L. V. Dickson and W. R. Fisher at Cornell University. About 

 one-eighth the actual size. 



sclerotia and their apothecia were arranged upon a layer of wet 

 cotton wool on a glass plate. The plate and fungi were then 

 covered with an inverted crystallising dish six inches in diameter. 

 Thereupon the whole was placed out-of-doors in a shaded spot, and 

 it was left there for three days whilst the ascospores matured. 

 About two hours before the photograph was to be made, the dish 



