PEZIZALES 



337 



degeneration of the trichogyne nuclei, an open communication forms 

 between the two groups of organs, the male nuclei migrate through the 

 trichogyne into the ascogonium which develops in the usual manner to 

 ascogenous hyphae. 



Meanwhile the gynophore below the ascogonia develops sterile sheath 

 hyphae which surround the sexual organs and later support the loose 

 apothecia (Fig. 223, 5). They serve in addition, as Pyronema, for the 

 nourishment of the growing asci as the reserve materials in their end 

 branches (the paraphyses) disappear at the maturity of the asci. 



As in Pyronema confluens, so also in Ascodesmis nigricans, the male 

 nuclei may degenerate prematurely in the antheridium. In this case 

 amphimixis is absent and the female nuclei pair autogamously in the 



Fig. 224. — Pushdaria vesiculosa. 1. Conidiophore from mycelium. 2. Tip of conidio- 

 phore after discharge of spores. 3 to 5. Ascospores and germ tubes developing directly to 

 conidiophore. Plicaria repanda. 6. Branched conidiophores. 7 Germinating conidia. 

 8. Mature ascus. (1 to 6 X 200; 7, 8 X 240; after Brefeld.) 



interior of the ascogonium and migrate into the ascogenous hyphae, as 

 in cross-fertilized ascogonia. Thus amphimixis is no longer obligatory 

 but facultative and, according to external conditions, may be replaced by 

 autogamy. 



The hemiangiocarpous Operculatae connect through the Ascobolaceae 

 and Pezizaceae directly to the Pezizaceae. These two families differ 

 from the Pyronemaceae in the higher development of their fructifications. 

 The hypothecium is no longer homogeneous as in Pyronema, but is dif- 

 ferentiated into a fleshy, occasionally colored peridium and a true ground 

 tissue, the hypothecium. Similarly the hymenium is no longer, as in the 

 Pyronemaceae (insofar as the latter possess a hymenium), open and con- 

 vex but typically concave, patelliform and, in most forms, angiocarpous. 

 Naturally the transition from the Pyronemaceae is only gradual. In the 

 Ascobolaceae a few forms are still known, e.g., Ascobolus stercorarius (A. 



