336 



COMPARATIVE MORPHOLOGY OF FUNGI 



mictic sexual act is no longer obligatory for Pyronema confluens, but is 

 facultative; its presence or absence and the necessary compensation 

 by autogamy depends only on nutritive relationships. 



In contrast to Pyronema, the second genus, Ascodesmis (Claussen, 

 1905; Dangeard, 1907), is connected ontogenetically to the Amauroascus- 

 Aphanoascus type of the Plectascales. Ascodesmis nigricans (Boudiera 

 Claussenii) is coprophilous on rabbit dung. In the development of 

 fructifications, a thick branch on any hypha is raised perpendicular to 

 the substrate and after a short time attains a T shape by forking (Fig. 



1 <? 



Fig. 223. — Ascodesmis nigricans. Development of fructifications, 

 ment of sexual organs. 5. Young fructification, slightly compressed. 

 540; 4 X 860; 5 X 380; after Claussen, 1905.) 



1 to 4. Develop- 

 Cl, 3 X 670; 2 X 



223, 2). Each bar of the T forks in a parallel plane near the substrate 

 twice or more, so that finally there arises a structure shown in Fig. 223, 3. 

 This structure (multinucleate) is called gynophore (Lotsy, 1907). It 

 is ab jointed from the hypha and subsequently develops to numerous 

 helical ascogonia which in turn are abjointed. 



In their vicinity, from the same original hypha are one or more 

 branches (androphores) forking to form antheridia which subsequently 

 coil helically around the ascogonia. Thus there are formed structures 

 shown in a simple case in Fig. 223, 4. 



The antheridial branch (approximately quinque nucleate) remains un- 

 divided ; the female branch is septate and divides into a short bi- to tri- 

 nucleate, apical trichogyne, and a longer, about quinque nucleate, 

 ascogonium. Hereupon, apparently as in Pyronema confluens, after the 



