TILLETIA TRITICI 



265 



upwards and strikes the under surface of a cover-glass, just as in the 

 Hymenomycetes, 1 it sticks to the glass where it strikes (Fig. 132, b). 

 In each experiment the cover-glass was placed at a definite 

 distance above the surface of the agar and left there for several 

 hours. At the end of this time, the under surface of the cover- 

 glass was examined with the microscope to find out whether or not 

 any basidiospores had become ad- 

 herent to it. In a series of experi- 

 ments the height of the cover-glass 

 above the agar varied from 0-5 to 

 1 • 1 mm. To determine the maximum 

 height to which the mycelium pro- 

 jected above the surface of the agar, 

 immediately after the completion of 

 the series of experiments a vertical 

 section was made through the my- 

 celium and agar and the amount of 

 projection was measured with the 

 microscope. In every experiment in 

 estimating the height of basidiospore- 

 discharge, the maximum distance of 

 projection of the mycelium was de- 

 ducted from the vertical distance 

 between the upper surface of the 

 agar and the under surface of the 

 cover- glass . Altogether , four complete 

 series of experiments were made. 



Fig. 132. — Tilletia tritici. Height to which 

 the basidiospores are discharged ; p, a 

 Petri dish containing malt -agar a at the 

 surface of which there is a mycelial mat 

 discharging basidiospores ; c, part of a 

 cover-glass supported in the air above the 

 mycelium. The basidiospores which are 

 shot high enough to touch the under side 

 of the cover-glass stick there, as shown 

 at b. The scale on the left enables one t < > 

 determine the height to which the basidio- 

 spores were shot in the particular experi- 

 ment illustrated. Magnification, about 1.'}.'!. 



o-s 



02. 



Oi 



^ 



A. H. R. Buller, Researches an Fungi, Vol. II, 1922, j>. Hi. 



