52 THE LOWER FUNGI— PHYCOMYCETES 



and the Myxomycetes would be provided, but the data concern- 

 ing germination arc so few and contradictory that conclusions 

 may not yet be safely drawn. In Plasmodiophora the amoeboid 

 character described by Woronin was not observed by Chupp 

 (1917). In Spongospora according to Johnson (1908) eight 

 zoospores are freed from the spore, while Kunkel (1915) describes 

 but one. In Ligniera the number varies, according to Cook 

 (1928 b), from four to eight. The assumption that the zoospore 

 penetrates the host directly without first encysting on the surface 

 in an enveloping membrane also requires verification. If true 

 it may perhaps be regarded as evidence of relationship with 

 the Synchytriaceae. 



In the host the earliest stages observed show these parasites 

 (except in Spongospora according to Kunkel) as intracellular, 

 uninucleate, amoeboid protoplasts, and it may be assumed in 

 most cases at least that they penetrate in this form. In the 

 host cell the protoplast (myxamoeba) becomes multinucleate, 

 increases in size, and absorbs nutriment from the host. It may 

 or may not fragment into daughter myxamoebae. At maturity 

 each myxamoeba is split by cleavage planes into uninucleate 

 bits, each of which envelops itself in a wall and assumes a more 

 or less spherical form. These bodies have been termed spores 

 by all workers in the group. After passing through a period of 

 rest, however, they germinate by one or more swarmspores or 

 myxamoebae, and seem to be comparable in many respects 

 to the resting sporangia of other families of the Chytridiales. 

 The same is true also of the so called spores of the Myxomycetes. 

 These "spores" (resting sporangia) may remain attached to 

 one another forming groups of definite form, or they may fall 

 apart and lie free in the host cell. 



The mature multinucleate myxamoeba which fragments to 

 form these spores apparently remains naked in most cases, so 

 that the spores are not enveloped in a common soral membrane; 

 but Schwartz states clearly that such a membrane is formed in 

 Sorosphaera. The papers of Borzi (1884: 6) and Nemec (1911 a; 

 1913 a) on Rhizomyxa, Sorolpidium, and A msom?/.ra lend support 

 to the assumption that both types of development exist in the 

 group. If this is true the group in this respect is intermediate 

 between the Myxomycetes and the Synchytriaceae. 



The peculiar phenomenon of elimination which in the Myxo- 

 gastres results in the formation of capillitium threads and 

 "sporangial" walls is wholly lacking in the Plasmodiophoraceae. 



