76 



MANUAL OF BOTANY 



wall. The spores have their own proper coats, which are much 

 thicker and more resistent than the ordinary cell-wall. The 

 zoogloea stage is generally the one in which the plant forms its 

 spores. 



It is to tliese organisms chieflj" that the processes of fermen- 

 tation and putrefaction are due, though other fmigi take part in 

 similar phenomena. 



Sub-Class II. — Myxomycetes. 



This curious group is distinguished by the fact that, except at 

 a particular time in its life, it possesses no cell- walls. Originating 



Fig. 829. 



F/v. 829. A. Plasmodium of a Myxomycete( X 300). B. A fructification still 

 closed, c. After rupture of the wall, p, and extrusion of the capillitium. 

 After De Bary x 20. 



from spores, the contents of the spore escape as a naked mass 

 of protoplasm, which in some forms is capable of active move- 

 ment by means of a cilium, and in others can only creep about 

 slowly, by means of protrusions which it can put out from its 

 substance. These are called ijseiidopodia. In the first case, 

 the freely motile body passes over later into this stage, so that 



