Seaver: Studies in pyrophilous fungi 67 



Explanation of plate 4- 



Pyronema omphalodes 



1. Normal ungerminated spore. 



2. Spores slightly swollen and apparently about to germinate. 



3-7. Stages in the germination of spores on the third morning after planting. 



8. Young ascogonia. 



9-10. Ascogonia and antheridia, side and end view. 



11. Mature ascus. 



12. Ascus showing dissemination of spores. 



13. Anastomosing mycelium. 



All figures are drawn with the camera lucida; 1-7 and 13 show stages in the de- 

 veloping spores collected in the spring of 1909 and germinated January 191 2, as they 

 appeared on the third morning after planting. 



