50 INTRODUCTION TO THE STUDY OF FUNGI 



is technically a sporangium. This apical receptacle is delicate, 

 membranaceous, and often transparent, enclosing a number of 

 small spores or zoospores. The mucors develop only spores 

 within the sporangia, but the Peronosporaceae sometimes pro- 

 duce only passive conidia at the ends of the branchlets, in 

 which case they belong to the naked -spored group, to be 

 alluded to shortly, in consort with the moulds ; at other times 

 sporangia are produced, or analogous organs, the contents of 

 which are differentiated and escape from the vesicle as zoo- 

 spores. These are the only instances known in Fungi in 

 wliich the hyphae support a delicate inflated vesicle containing 

 spore-bodies capable of germination. This is not the only 

 feature in which they differ materially from the moulds which 

 they superficially resemble ; but in the mycelium they differ 

 in the hyphae being for the most part without septa, and 

 further, in the power which they possess in forming special 

 branches on the mycelium, which conjugate and form zygospores. 

 These latter are able to pass through a period of rest, as rest- 

 ing spores, and form a second form of fruit for the mucors ; as 

 oospores are produced on the mycelium of the Peronosporaceae 

 by a similar sexual act, and are a second form of fruit for that 

 family, capable of passing the winter as resting spores. 



Having disposed of the several forms of fructification 

 which are to be found developed within special envelopes, or 

 receptacles, according to their kind, we have still to deal with 

 those less common forms in which the fructification is naked 

 on the carpophores, and destitute of any kind of receptacle. 

 The most typical of this system of fructification is that 

 exhibited by the moulds, or Hyphomycetes, in which the 

 carpophore or conidiophore is either simple or branched at the 

 apex, and the spore-bodies, or conidia, are produced singly or 

 in clusters at the apex of the conidiophore, or at the tips of 

 its branches, or diffused in any other manner upon its surface. 

 It may at once be admitted that in these nakedly-disposed 

 spore -bodies we are unable to recognise any symptoms of 

 sexuality, and hence they can scarcely come under any other 

 designation than that of reproductive buds, or if that term 

 is objected to, then as asexual spores. If we accept as an 

 example Verticillium agaricinum, the carpophore is an erect, 



