FUNGI IN GENERAL 105 



The second subdivision of the Ascomycetes differ chiefly 

 in the character of the receptacle, which is fleshy or leathery 

 and cup-shaped, and only closed when very young, but soon 

 expanded, reaching in some cases a diameter of several inches, 

 but often much smaller or very minute. The disc, or inner 

 surface, of these cups is compact, rarely gelatinous, and consists 

 of the hymenium, or fruit-bearing surface, which is composed 

 of asci and paraphyses, closely packed side by side. The great 

 feature, then, which distinguishes this subdivision from the 

 last is the open or cup-shaped receptacle and the exposed disc, 

 or hymenium, and hence called the Discomycetes. 



A small section occupies a position somewhat intermediate 

 between these two large orders, possessing some of the char- 

 acters of both. The perithecia are black and leathery or almost 

 carbonaceous, closed at first and when dry, but opening when 

 moist with a longitudinal fissure, and then gaping and exposing . 

 the hymenium ; so that whilst it approaches the Pyrenomycetes 

 in texture, and to some of them in the elongated mouth, it 

 comes near to Discomycetes in the compact exposed disc, so 

 that sometimes it has been united with one subdivision and 

 sometimes the other. In both cases it is maintained as a 

 distinct order under the name of Hysteriaceae. 



In addition to all these are those subterranean Fungi, of 

 which some are called Truffles, in which, although the spores 

 are contained in asci, the latter are not enclosed in a peri- 

 , thecium, as in Pyrenomycetes, nor arranged in a disc, as in 

 Discomycetes, but are dispersed throughout the whole sub- 

 stance, within folds or cavities, and are not expelled or set 

 free, except by the decay and dissolution of the entire fabric. 

 These are the Tuberaceae. 



In order to complete this general survey of the chief larger 

 groups of Fungi, we must allude briefly to a somewhat confused 

 section, which still maintains the old name of Phycomyceteae, 

 somewhat extended in its scope. It will be observed that 

 although the spores ,or conidia are naked in some genera, as 

 they are in the moulds, they are in other cases enclosed within 

 a common membrane, suggestive of Ascomycetes. The feature 

 which is relied upon for holding together this rather hetero- 

 geneous agglomeration of genera, is their sexuality, extending 



