in CLASSIFICATION OF FUNGI 33 



class consist of irregular, branching mycelium ; they 

 reproduce non-sexually by means of both conidia and 

 sporangia, and sexually by the union of two unequal or 

 dissimilar structures, which are also known as gametes. 



Under Sub -class 1, the Archimycetes, will be 

 considered but a single order : 



Order 1. CHYTRIDIALES. The members of this order 

 are very small, unicellular, and parasitic upon many 

 plants, although of no great economic importance. In 

 many instances they stimulate the growth of certain 

 cells of the host plant and cause the formation of 

 numerous small swellings or galls (Fig. 21). These 

 galls may be the result of the 

 swelling of the cell within which 

 the fungus lives, or they may be 

 caused by the swelling of that and 

 the neighbouring cells. The many 

 species of this order are known to 

 attack cabbage and apples and 



i-ii if 1 FIG. 21. Gall containing 



many wild plants, but are not syncharium. 



considered of any great economic 



importance. Small, free-swimming spores are produced 

 which escape from the host plant and swim in the 

 water, or in the moisture on the surface of the plant in 

 the case of land plants. These spores eventually come to 

 rest, penetrate the new host and grow into mature plants. 



The sub-class Zygomycetes consists of two orders, 

 Mucorales and Entomophthorales. 



Order 2. MUCORALES. This order includes the 

 most common black moulds, 1 and they are mostly 

 saprophytic, but some are parasitic on other moulds. 

 The best example of this order is Khizopus nigricans 2 

 Ehr. (Figs. 11 and 12), or common bread mould, 

 which develops readily on bread when left for a few 

 days in a damp, warm place. It consists of great 

 quantities of white, irregular, branching mycelium, which 

 penetrates the bread and gives rise to upright branches, 



1 For green mould, see Penitillium, page 43. 

 2 Mucor stolonifcr. 



