568 A MANUAL OF BACTERIOLOGY 



sporangium as a sporangiophore. Some moulds produce spores by 

 segmentation of hyphse, these conidia being known as o'idia. 



The Fungi are divided into the Phycomycetes, Ascomycetes, 

 Basidiomycetes, and Fungi Impeiiecti. The Phycomycetes are 

 distinguished by non-septate or slightly septate hyphse and zygo- 

 spore-formation, as in the Mucors. The Ascomycetes are charac- 

 terised by the cell resulting from fertilisation giving rise to 

 other cells, some of which become spore sacs or asci containing 

 several spores. Asexual spores are usually produced as well. 

 The Basidiomycetes have spore-bearing structures known as 

 basidia ; the rusts, smuts, toadstools, puff-balls, and mushrooms 

 belong to this group. All fungi which do not fall into one of 

 these three groups are placed among the Fungi Imperfecti ; most 

 of them probably belong to the Ascomycetes. Mucor mucedo, 

 Penicillium glaucum, and Aspergillas niger may be taken as types 

 and more fully described. 



Mucor mucedo 



The Mucomcice belong to the Phycomycetes, and are divided 

 into some eighteen genera. 



Mucor mucedo, the common white mould which appears like 

 tufts of cotton-wool on various substances, may be obtained by 

 exposing some moistened bread or horse-dung to the air for a 

 short time, and then keeping it moist under a bell- jar. It con- 

 sists of a mycelium composed of hyphse, and its fluffy appearance- 

 is caused by aerial hyphae. The aerial hyphse are at first of even 

 diameter throughout, but later on their free ends become swollen 

 and ultimately form spherical bodies, which become filled with 

 spores, the sporangia. In the early stage the whole organism 

 forms but a single cell, the protoplasm of which is granular and 

 contains vacuoles and numerous small nuclei. As it grows, and 

 the sporangia form, these become separated by a septum from the 

 hyphse, and when it becomes older still the mycelial hyphse may 

 be divided into elongated cells. The development of a sporan- 

 gium takes place as follows : The distal end of an aerial hypha 

 swells, and immediately below the swollen part a division occurs 

 in the protoplasm and a cellulose septum is formed, so that the 

 swollen part is separated off from the rest of the hypha, forming 

 the rudimentary sporangium. The sporangium continues to 



