1 48 



PYRENOMYCETES 



[CH. 



two nuclei each. In his opinion, the second nucleus in the originally uni- 

 nucleate cell, is derived from its multinucleate neighbour, which he terms 

 the antheridium ; the other binucleate cells receive their nuclei from it by 

 conjugate division, and are the beginnings of ascogenous hyphae. Though 

 he was unable to see either the entrance of the second nucleus, or the 

 process of conjugate division, his facts are decidedly suggestive, but they 

 point less to normal fertilization than to the pseudapogamous association 

 of a vegetative and a female nucleus. 



The binucleate character of the later formed large cells may, as he 

 suggests, be due to conjugate division, but, since he finds that the numerous 

 binucleate cells in the sheath' are the result of rapid growth, this character 

 in the large cells is evidently susceptible of the same explanation. In an}^ 

 case the rest of the archicarp degenerates and owing to the refractory 

 character of the material the ascogenous hyphae could not be further traced. 



According to Blackman and Welsford, all the cells of the archicarp 

 degenerate without giving rise to ascogenous hyphae, and being functionless, 

 retain their contents so that they can be recognized during the later stages 

 of development as densely staining masses (fig. io8). The perithecia (fig. 

 109) arise in their neighbourhood, one in association with each archicarp, 

 and the vegetative cells produce ascogenous hyphae, which become dis- 

 tinguished by their large size, dense contents and well-marked nuclei. These 



Fig. 108. Polystigma rubrum DC; young perithe- 

 cium; the ascogenous hyphae are not yet clearly 

 distinguished, many of the nuclei are in pairs, the 

 darkly stained remains of the archicap are visible 

 near the periphery; x68o; after Blackman and 

 Welsford. 



Fig. 109. Polystignia rubrum DC-; mature peri- 

 thecium, x 270; after Blackman and Welsford. 



• Nienburg, p. 390, end of first paragraph. 



