Atanasoff: Method of Ascospore Discharge 127 



The ascospores before and during the swelHng of the ascus are 

 distributed uniformly throughout the ascus. After the formation 

 of the ring, however, partly because of the rupturing and con- 

 traction of the outer wall, but more particularly because of the 

 thickening of the inner wall, especially in the lower part of the 

 ascus, there seems to be an upward movement of the ascus con- 

 tents and usually before the breaking of the inner wall all asco- 

 spores are above the ring. Occasionally it was observed that 

 single spores remained below the ring, but such spores usually 

 remain inside the ascus even after the breaking of the inner wall. 



Fig. 3. Camera lucida drawing of group of asci, showing: a, swollen 

 ascus with contracting outer wall ; b and c, ruptured asci with ascospores lying 

 as discharged. 



Only in very rare cases, mostly in improperly developed asci, are 

 there any spores left in the upper part of the ascus after the 

 breaking of the inner wall. 



The time that elapses from the moment of the liberation of the 

 ascus from the perithecium to the time of its swelling and the 

 rupturing of the outer wall varies considerably. It may take 

 only a few seconds (15-30) or even several minutes or longer. 

 The length of the time that elapses from the rupturing of the 

 outer wall to the rupturing of the inner wall varies also. In 

 some cases it is less than 30 seconds ; in others it may be as long 

 as 30 minutes. 



