Seaver: Studies in pykophilous fungi 65 



The spores germinate by putting out a germ tube from each 

 end, one end, however, growing much faster than the other. The 

 young mycelium is very coarse, the diameters of the main branches 

 being fairly constant. The whole mycelium is filled with vacuoles, 

 giving it a characteristic appearance. The spore before germi- 

 nating swells much, becoming large and very granular. The germ 

 tube as it issues from the spore is slightly smaller in diameter 

 than the spore but often swells to about the same diameter. 

 The contents of the spore after germination are similar in appear- 

 ance to the contents of the young mycelium, and there appears to 

 be no difference between the wall of the old spore and that of the 

 young mycelium, the spore forming one segment in the growing 

 mycelium, usually of a little larger diameter and shorter but often 

 so nearly like the other segments of the mycelium that it is difficult 

 to determine the position of the old spore. In some cases the 

 spore seems to swell up and begin to grow by simply cutting off 

 new segments at either end. 



The spores of Pyronema, as shown in the present experiment, 

 will keep their viability for nearly three years; as to how much 

 longer they will remain good we cannot at present say. Griffiths* 

 in his work on Fimetariaceae (Sordariaceae) found one species 

 in which the spores kept their viability for more than three 

 and one-half years. 



The demonstration of the long viability of the spores of 

 Pyronema is one more argument in favor of the introduction of 

 this fungus into college and university courses in botany which 

 deal with a general knowledge of the subject. The cultivation 

 of the fungus requires no complicated technique, and the rapidity 

 with which the plant grows would enable the student to study all 

 of the stages from the germinating spore to the production of 

 sex organs and mature ascocarps within a period of about ten 

 days. Also, the asci of Pyronema when mounted in water illus- 

 trate very nicely the common method of spore dissemination among 

 the ascomycetes. 



Claussenf in his recent paper on the development of Pyronema 



* Griffiths, D. The North American Sordariaceae. Mem. Torrey Club ii: 

 1-134. pi. 1-19. 30 My 1901. 



t Claussen, P. Zur Entwicklungsgeschichte der Ascomyceten, Pyronema con- 

 fluens. Zeit. Bot. 4: 1-80. pi. 1-6. 1902. 



