624 COMPARATIVE MORPHOLOGY OF FUNGI 



no longer occurs; in still other forms, as the Amauroascus-Ctenomyces- 

 Aphanoascus group of the Plectascales and in Pyronema confluens, var. 

 inigneum of the Pezizales (p. 169 and 335), they no longer fuse with the 

 ascogonia; at least in Pyronema confluens, var. inigneum, however, they 

 coil about the trichogyne several times and finally, in forms such as 

 Penicillium vermiculatum (p. 180), they are retarded and are only ready 

 to function when the ascogonia have passed capability of fertilization. 

 In all these cases the nuclei in the ascogonium pair autogamously and 

 continue to develop as if copulation had occurred. 



In the direct relations of all these forms a morphological as well 

 as a functional weakness of the antheridia develops; the functionless 

 antheridia are eventually no longer formed and the ascogonia are solitary, 

 as in the Aspergillus herbariorum-A. flavus series of the Plectascales 

 (p. 182), in the Melanospora-Neurospora series of the Hypocreales (p. 

 226), in the Chaetomium globosum-C. spirale series of the Sphaeriales 

 (p. 257), in the Ascobo^us magnificus-A. citrinus series of the Asco- 

 bolaceae (p. 338) and in the Lachnea scutellata-L. stercorea series of 

 the Pezizaceae (p. 343) in the Pezizales. That this morphological 

 degeneration is similar in very different orders allows one to assume a 



fundamental law. 



As compensation for this lack of organic cross fertilization by the 

 degeneration of the antheridium, two groups of substitute functions 

 appear subsequently one of which is reminiscent of the earlier cross 

 fertilization, while the other leads directly to autogamy. 



In the first group, to which belong Ascobolus carbonarius of the 

 Pezizales (p. 340) and Collema pulposum and C. crispum of the Disco- 

 mycetous lichens (p. 350), the trichogynes, for lack of antheridia, 

 copulate with imperfect forms, conidia and oidia. To explain these 

 relationships, one may assume, in consideration of the relationships of the 

 Basidiomycetes, that some of these forms are heterothallic; although the 

 male mycelium by the loss of antheridia has morphologically become 

 imperfect, they retained (as the later pseudogamous types show) their 

 sexual character, so that thereafter the imperfect forms in place of the 

 only slightly differentiated antheridia assume the function of male 

 sexual cells. In the homothallic forms, one must imagine that the asco- 

 gonia, for some reason or other, possess a stronger affinity to these imper- 

 fect forms than to the usual mycelial cells. 



This conidial copulation actually causes great difficulties in the mono- 

 phyletic derivation of fungi proposed in this book and other equally 

 unsatisfactory explanations are offered. Thus Dangeard considers 

 that in primitive gametangia, e.g., of the Monoblepharis type, the male 

 gametes lost their motility and became male akinetes which might have 

 appeared similar to the sporangiospores of the Mucoraceae. Just as 

 these sporangiospores of the Mucoraceae gradually developed exo- 



