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TEXT-BOOK OF FUNGI 



in the Basidiomycetes; after fusion of the nuclei the oospore 

 is formed. 



The germination of this oospore is in every respect com- 

 parable with that of the Basidiomycetes, and takes place 

 immediately. The oospore grows into the ascus, in which 

 the sexual nucleus usually undergoes three successive 



FIG. 30. Stages showing the formation of an ascus from the 

 apex of an ascogenous hypha in Peziza badia. i, the terminal 

 cell forming a hook, and containing three nuclei ; 2, the ter- 

 minal portion of the hook containing one nucleus cut off by a 

 septum, the penultimate cell containing two nuclei is the 

 young ascus ; 3, the two nuclei in the young ascus commenc- 

 ing to fuse ; 4, young ascus elongating and showing complete 

 fusion of its two nuclei. This sequence illustrates the develop- 

 ment of a binucleate oospore according to Dangeard's view. 

 All highly mag. 



karyokinetic divisions, thus forming eight nuclei, corre- 

 sponding to the usual number of spores present in an 

 ascus. 



The mode of formation of spores is slightly different; 

 in the Basidiomycetes they are exogenous, in the Asco- 

 mycetes they are produced in the interior of the ascus, or 

 endogenous. 



Such are the broad outlines of Dangeard's conception 

 of sexual reproduction in the higher fungi, which it must 



