ASCOMYCETES 355 



shown that it contains a relatively large proportion of glycogen, he has 

 more lately (' Comp. Morph.,' p. 77) adopted for it the term glycogen-mass 

 or simply the glycogen. In certain cases the separation of the glycogen 

 from the protoplasm takes place before the formation of spores, the 

 former occupying the lower part of the ascus, and in some instances 

 both the apical and the basal portions on either side of the protoplasm 

 in which the nucleus is situated and the ascospores are formed. 



Such are the asci which characterise the great class of Ascomycetes. 

 They are borne as a rule in considerable numbers mostly between hair- 

 like bodies, the paralyses, and united into hymenia within special sporo- 

 carps. The sporocarps are either seated on a fine mycele or they are 

 borne on a large stroma (thallus), which assumes in different genera 

 diverse characteristic forms. The whole body of the Ascomycetous 

 type is always built up of septate hyphse. 



The sporocarps are composed of two main elements of the asci with 

 the ascogenous hyphse, and of the envelope including paraphyses. These 

 two elements, though much interwoven with each other, are of dis- 

 tinct origin. The paraphyses, for example, are never borne by the asco- 

 genous hyphae, and the asci never by the cells of the envelope ; at all 

 events the one thing certain about so-called exceptions is their doubtful 

 character. According to the structure of the mature sporocarp, the 

 Ascomycetes may be classed in three divisions : the Discomycetes^ with 

 discocarps or apotheces (hymenia exposed) ; the Pyrenomycetes, with 

 pyrenocarps or peritheces (hymenia within flask- shaped bodies open at 

 the neck) ; and a third assemblage of forms with cleistocarps (enclosed 

 hymenia). 



The hymenial disc of the apothece, consisting of asci and paraphyses 

 placed perpendicularly to the surface, is when ripe fully exposed. The 

 asci are imbedded, so to speak, in the paraphyses, and the whole mass 

 terminates in a regular surface. The paraphyses originate beneath from 

 a dense plexus of hyphae called the subhymenial layer or hypothece y 

 directly continuous with the outer envelope termed the exciple or with 

 the tissue of the stroma as the case may be. The paraphyses thus form 

 a part of the envelope-tissue as distinguished from the ascus-apparatus. 

 The ascogenous hyphae are interwoven with those hyphae of the hypo- 

 thece which bear the paraphyses. Terminating upwards in the asci 

 they are barely otherwise distinguishable in the mature apothece, unless 

 in certain cases by their greater size and the blue colour they assume 

 after treatment with potash. The asci grow up between the paraphyses^ 

 and reach the surface, as has already been indicated, about the period 

 of ripening. As a rule the apothece exhibits a regular progressive 

 marginal growth, with, in a considerable number of cases, an intercalary 



