3S British Fungi, 



originate in various ways_, some sexual^ otiiers asexual. 

 Tlien again, in the Bcmdiomycetes, where there is sup- 

 posed to be no trace of sexual organs, we find differ- 

 ences of degree in the spores, as basidiospores and 

 the organs we have called gonidia. Numerous 

 classifications of the various kinds of spores have 

 been suggested from time to time, and every classifier 

 as a matter of course gives a new set of names to the 

 various forms. But all such arrangements are prema- 

 ture, for the simple reason that we do not know the 

 relative functions or orisfin of the various kinds. As 

 an example, it has been suggested that the term spore 

 should be reserved for reproductive cells of sexual 

 origin. This idea answers very well for what we have 

 called oospores and zygospores, where the sexuality 

 is placed beyond doubt and universally admitted, but 

 when we come to ascospores a grave difficulty arises, 

 because, as already stated, the best authorities are 

 diametrically opposed in opinion as to the presence 

 or absence of sexual organs of functional value in the 

 Ascomycetes. Equally grave difficulties present them- 

 selves in connection with what we have termed 

 gonidial forms. 



Using the term spore in the broader sense already 

 indicated, the general structure is as follows : — when 

 ripe the cell-membrane consists of two layers, an 

 outer, the exospore or epispore, and an inner, the 

 endospore ; these may in turn be stratified, and, on 

 the application of sulphuric acid, split up into several 

 layers. In acrogenously formed spores, that is, spores 

 formed by differentiation of the tip of a hypha, as 

 basidiospores, in addition to the epispore and endo- 



