PLASMODIOPHORALES 



Tetramyxa 37 



Octomyaxi 40 



Sorosphaera 41 



Sorodisciis 46 



Membranosorus 52 



Spongospora 54 



Llgniera 58 



Polymyxa 63 



Doubtful genera 64 



Rhizomyxa 64 



Sorolpid'uim 66 



Anisomyxa _ . . 68 



Trematophlyctis 70 



Pyrrhosorus 71 



Excluded genera 72 



Sporomyxa 74 



Peltomyces 76 



Cystospora 76 



CHAPTER V 



Phylogeny and relationships of the Plasmodiophorales 78 



Historical 78 



Relationships with the Myxomycetes 79 



Relationships with the Chvtridiales 85 



Relationships with Woronina 85 



Relationships with the Proteomyxa and Protozoa 88 



Bibliography 91 



CHAPTER VI 



• 



Diseases caused by species of the Plasmodiophoraceae 93 



Club root of crucifers 93 



Losses due to disease 93 



Discovery of disease 93 



Symptoms 93 



Cellular relations between host and pathogen 95 



Entrance and spread of parasite 96 



Dissemination of parasite in nature 96 



Environmental factors 97 



Hosts and degree of infection 99 



Control of club root 104 



Sanitary practices 104 



Seed, seed bed, and seedling disinfection 105 



Disinfection of fields 105 



