300 



COMPARATIVE MORPHOLOGY OF FUNGI 



Meanwhile the surface of the plectenchymatic cushion has become 

 brown and chitinized. At its tip is differentiated a small papilla which 

 later breaks off and leaves a circular hole through which the ascospores 

 escape (Fig. 196). At the periphery, the aliform surface layer extends 

 over the edge of the narrow perithecium and ends blindly. Thus it 



Fig. 196. — Stigmatea Robertiani. Section through a fructification. (X 341 ; after Kle- 



bahn, 1918.) 



Fig. 197. Fig. 198. 



Fig. 197. — Stigmatea Robertiani. Surface view of the subcuticular mycelium which 

 merges at its lower edge with the outer layer of the fructification. ( X 804 ; after Klcbahn, 

 1918.) 



Fig. 198. — Stigmatea Robertiani. Portion of the edge of the fructification. {After The- 

 issen and Sydow, 1917.) 



forms only the central part of a scutellate cover which gradually con- 

 tinues outward into the original mycelial membrane (Fig. 197). Seen 

 from above, the elements radiate in waves and themselves often form 

 secondary centers of radiation (Fig. 198). 



This life cycle of S. Robertiani is notable in three respects. First, 

 its fructification no longer has a perithecial wall, but is an apothecia-like 



