MOULDS. ISO- 



state that one of tlie six families into wliicli fangi 

 are divided for scientific purposes is called Hyplio- 

 mycetes, a name compounded of two Greek words 

 signifying "tkread^^ and ^^mould/^ or " fungus/' 

 and is applied to this group because the thread- 

 like filaments of which they are largely composed 

 are the most prominent feature. In this family 

 there are again a number of smaller groups called 

 orders, having an equal value to the natural orders 

 of flowering plants ; and one of these orders, called 

 Mucedines, has the fertile threads perfectly distinct 

 from the mycelium or spawn. These threads are 

 sometimes simple and sometimes branched; they 

 may be articulated or without articulations or septa^, 

 short or long, erect or creeping, hyaline or whitish, 

 mostly free from colour, and are not coated with 

 a distinct membrane. The spores are generally 

 simple, sometimes solitary, at others in paks, or 

 strung together like beads for a necklace. Amongst 

 all this variety of arrangement there is order, for 

 these are but features, or partly the features, of the 

 different genera of which the Mucedines are com- 

 posed. One of the genera is termed Peronospora, 

 and to this the parasitic fungus of the potato, and 

 some others to which we shall have occasion to 

 refer, belong. In this genus the threads are 

 generally branched, but without articulations. The 

 spores, or seed-like bodies, are of two kinds ; one 

 kind is borne on the tips of the branches ; and the 

 other kind, which is larger and globose, is borne 



