M. 0. COOKE ON BLACK MOULDS. 249 



bring science, in so far as Mycology is concerned, into contempt. 

 Not being able, under these circumstances, to submit to you an 

 absolutely physiological communication, and being prevented by a 

 regard for your patience from inflicting upon you one that is 

 entirely systematic, you will probably be disposed to accept as a 

 compromise something intermediate between the two, although it 

 might prove unworthy of either. 



The division of Hyphomycetes selected for this occasion are known 

 as the Dematiei, or black moulds. The chief distinction lies in the 

 dark colour of the threads, and the black, sooty, or dull -coloured 

 patches in which they are collected. Nearly seven years ago I had 

 the honour of reading a paper to the Club " On Microscopic 

 Moulds," which was published in No. 11 of the" Quekett Journal," 

 with illustrative figures, to which I shall have occasion to allude. 

 In that paper I gave a kind of running commentary upon all the 

 moulds, and pointed out the distinctions between them. It will not 

 be necessary to cover this ground again, but refer members to the 

 Journal in question for such points as may be omitted here. The 

 figures given of Mucedines, and of Black Mould, will enable com- 

 parisons to be instituted, and a general idea obtained of the dis- 

 tinguishing features of the two orders or divisions. 



Although it may impart somewhat of a repulsive formality, in the 

 estimation of some, to this communication, there will manifestly be 

 an educational advantage to be derived from adopting a sort of 

 scientific order and arrangement in the sequence of the species to be 

 alluded to. In pursuance of this plan, I will first remind you of a 

 simple form of black mould which is by no means uncommon in this 

 country, but is often found mixed up with other species. This 

 consists of a simple, rigid, erect stem, or thread, so dark as almost 

 to obliterate all appearance of septa ; at the apex is borne a single, 

 dark, nearly globose spore, without any transverse division. This is 

 termed Monotospora, and it may well be accepted as a simple 

 typical form of a black mould. There is the dark carbonised stem, 

 with branching brown root-like filaments at the base, and a single 

 spore growing at the summit. At first the tips of these threads 

 are colourless, the upper joint swells, and gradually increases until 

 it becomes pear-shaped, and then globose. It acquires colour, the 

 outer membrane thickens, the spore is divided from the thread by a 

 septum, and at length falls away. Technically and rigidly the 

 genus is confined to those species which have globose, or somewhat 



