every few minutes. The drawings presented in the accompany- 

 ing figure represent different stages in the growth which has 

 taken place on maltose agar during a period of two hours. The 

 first drawing (a) was made at 8:45 p. m., the second (b) at 9:00 

 p. m., the third (c) at 9:15 p. m., and the fourth (d) at 10:45 p. m. 

 Thus, during the usual two hour laboratory period a student is 

 able to make several drawings of different stages of growth and 

 to take measurements at regular intervals from which the rate 

 of growth of this organism may be calculated. At the same time 

 he is enabled to follow the formation of septa in the mycelium 

 and to study such structures as vacuoles etc. 



In connection with such classroom studies, it is well for the 

 instructor supervising the work, to plant the ascospores to be 

 studied on the agar plates, eight to twelve hours before observa- 

 tion is to begin, this being the time required usually for asco- 

 spore germination. When the first observation is about to be 

 made, the Petri dish is uncovered and a thin cover-glass is 

 placed on the surface of the agar covering the germinating asco- 

 spores. By following this procedure, studies can be made by the 

 use of the high power objective of the microscope whereas with- 

 out the cover glass, the lens, because of its proximity to the 

 moist surface of the agar, will cloud very quickly. 



Some of the other advantages of this fungus besides its 

 rapid growth which make it very suitable for elementary studies 

 are the following: The mycelial threads are stout, hyaline when 

 young and brown when old. The septa are placed fairly close 

 together and are sharply differentiated in the older brown 

 mycelium. The fungus produces perithecia in abundance on the 

 common laboratory agar media, the spores maturing about 

 twenty days after inoculation. The perithecia are large, dark, 

 and beaked. When these are crushed under a cover-glass, the 

 numerous asci spread out, and the ascospores, because of their 

 deep brown color, are sharply defined in their positions within 

 the hyaline ascus. The ascospores are large, measuring 16-26;u 

 in length and can be easily observed under the low power and 

 studied under the ordinary 44 X objective. 



Department of Biology, Kent State University 

 Kent, Ohio 



