HYPOCREALES 



231 



ground. Between the long, multinucleate, male and the long, uninucleate, 

 female cell, there is formed a pore (Fig, 148, 2) and one of the many male 

 nuclei migrates into the female cell. Then the pore is closed (Fig. 148, 3) 

 and the nuclei remaining in the male cell gradually degenerate. 



Not only the ascogonium but also the surrounding vegetative cells 

 show an increased vitality, probably because of stimulation of the sexual 

 act. They begin to change to rafter-like, super-imposed paraphyses, 

 while the ascogonium dies, except for the single cell with its dicaryon. 



m 



Fig. 149. — Poly stigma rubrum. 1. Part of mature ascogonium from which trichogynes 

 extend to the left above and below. 2. Continuation of lower left trichogyne of 1. 3. 

 Further continuation of the trichogyne of 2. (Note the renewed branching.) (X 860; 

 after Nienburg, 1914.) 



By forcing aside these paraphyses, the perithecial cavity, filled by para- 

 physes, is formed. During January the ascogenous hyphae grow into the 

 cavity and change to asci. In March the development of the ascospores 

 is completed. 



This life cycle of Poly stigma rubrum is generally interpreted according 

 to the relations of the lichens to be discussed later in the Discomycetes, 

 that the pycnia are spermogonia, and the structures here designated 

 as pycniospores (and they are certainly very difficult to germinate) as 

 functionless spermatia which earlier may have fertilized the ascogonia. 



