i 4 8 



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 1 are the result of rapid growth, this character 

 in the large cells is evidently susceptible of the same explanation. In any 

 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 the)- can be recognized during the later stages 

 of development as densely staining masses (fig. 108). 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 rubriim DC; young perithe- 

 cium; the ascogenous hyphae are not yet clearly 

 distinguished, many of the nuclei are in pairs, the 

 darkly stained remains of ihe archica'p are visible 

 near the periphery; x68o; after Blackman and 

 Welsford. 



Fig. 109. Polystigma rtibrutn DC ; matu 

 thecium, x 270; after Blackman and W 



re pen- 

 elsford. 



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



