882 LIFE-HISTORY OF PHOMA CITRICARPA. 



Figs. 20, 21. — Portions of sections through a mature pycnidium, showing 

 the outer layers of dark brown, thick-walled cells, lined bj' the 

 remains of the pseudo-parenchyma from which the spore-bearing 

 hyph£fi arise; ( x 480). 



Plate xc. 



Fig. 22. — Section through a pycnidium upon orange rind. The pycnidium 

 contains mature spores. The slightly increased development of the 

 outer layers of thick-walled, brown cells just beneath the ruptured 

 epidermis, is noticeable; ( x 480). 



Fig.23. — Section through a trilocular pycnidium grown upon orange-rind- 

 extract agar. There is a common outer covering, and the loculi 

 are separated by walls composed of fine hj'phai; ( x 120). 



Fig.24. — Section through a pycnidium in which "x' spores are being 

 abstricted from fine hyphfe; ( x 120). 



Fig. 25. — (Iroup of normal p3'cnospores and "x" spores discharged from a 

 pycnidium; ( x 480). 



