MYCETOZOA 



303 



h ^ c 



e f 





Fig. IBS. Plasinodiophora brassicae. a, root-hernia of cabbage; b, a 

 spore, X620; c-e, stages in germination of spore, X620; f, myxamoeba, 

 X620 (Woronin); g, a host cell with several young parasites, X400; 

 h, an older parasite, X400 (Nawaschin). 



cabbage and other Cruciferae. The organism produces knotty 

 enlargements, sometimes known as 'root-hernia,' or 'fingers and 

 toes' (Fig. 138, a). The small spore (h) gives rise to a myxo- 

 flagellate (c-f) which penetrates into the host cell. The organism 

 grows in size and the nucleus divides (g). Several myxamoebae 

 fuse into a plasmodium, thus destroying the host cells. The nuclei 

 undergo mitotic division and finally the plasmodium divides 

 into a large number of simple spores. 



P. hrassicae W. (Fig. 138). In the species of Brassica. 



Other genera are Sorosphaera Schroter, parasitic in Veronica; 

 Tetramyxa Goebel, forming gall in Ruppia, etc. 



References 



DE Bary. 1864 Die Mycetozoa. Leipzig. 



Jahn, E. 1901-1920 Myxomycetenstudien. I to X. Ber. 



Deutsch. Bot. Ges., Vols. 19, 20, 22-26, 29, 36 and 37. 

 Jones, P. M. 1928 Morphology and cultural study of Plas- 



modiophora hrassicae. Arch. f. Protistenk., Vol. 62. 

 Lister, A. 1924 A monograph on the Mycetozoa. 3rd ed. London. 

 MacBride, T. H. 1922 North American slime molds. 2nd ed. 



New York. 

 Palm, B. T. and Myrle Burk 1933 The taxonomy of the 



Plasmodiophoraceae. Arch. f. Protistenk., Vol. 79. 



