1893.] 



MICROSCOPICAL JOURNAL. 



125 



sketched from the same object at 3.15 P. M. on the same day, and 

 c at 11.45 ^- ^•' ^^^- i6th. The spores are therefore developed 

 with great rapidity under favorable circumstances. In the same 

 culture vs^ere other spores w^hich developed a much greater extent 

 of mycelium and num- 

 ber of spores. This 

 group was chosen be- 

 cause of its limited ex- 

 tent, being thus more 

 convenient to sketch. 



During the growth 

 and production of 

 spores the coarse 

 granules gradually 

 disappear. As the 

 culture ages the mass 

 of spores becomes 

 greater at the centre of 

 each group of- myce- 

 lium. In a few days 

 spore production 

 seems to cease and 

 then long sterile my- 

 celial threads grow 

 out to a considerable 

 distance. 



At the same time 

 there are usually de- 

 veloped buds or gem- 

 mae, at the ends of 

 certain threads. These 

 are colorless at first 

 and may be detected 

 by their irregularly 

 oval outline, and 

 greater diameter than 

 the parent thread. 

 They soon acquire a 

 dark brown color, 



sometimes become septate, or bud into rudimentary sclerotia. 

 One of these developed quite early in the culture is shown at .v, 

 figure 3. 



Spores were also sown on sterilized bean stems. The fungus 

 grew readily and produced numerous spores during a few days, 

 when the threads assumed a dark brown color and grew in great 

 profusion over the surface of the stems. Frequently the threads 

 associated themselves into strands, or compact wefts of parallel 

 threads several layers deep. Within these wefts and strands were 

 developed numerous bodies suggesting pycnidia, or perithecia, 



STAGES OF GROWTH PROM A SPORE. 



