UROPHLYCTIS 97 



nodulose outgrowths, sometimes the size of a walnut, and 

 attached by a narrow base are formed, consisting of modified 

 rootlets, or in some instances probably leaves ; the thick, 

 fleshy, primary root is not usually attacked. These tumours 

 contain numerous cavities filled with the resting-spores of the 

 fungus. The original cyst, instead of remaining simple and 

 rounded as in U. Kriegeriana, sends out irregular outgrowths, 

 which react on the surrounding parenchyma, causing rapid 

 division of cells, and consequent increase in size of the tumour. 

 The extensions of the original cyst in turn become inflated 

 and occupied by the fungus. This process is repeated until 

 eventually a large tumour is the result, its tissues enclosing 

 numerous cysts or spore-bearing cells, originating from each 

 other, and connected by necks or narrow passages. The 

 fungus is confined to the cysts, not entering the parenchyma. 

 The male conjugating cells are produced on different hyphae 

 to those giving origin to the female cells. At maturity 

 receiving cells become clothed with a thick, brown wall 

 having a depression on one side. These cells measure 

 45-50X30 /x. Swarm-sporangia have not been observed. 

 Saccardo founded the genus Oedomyces on this species, and 

 referred it to the Ustilaginaceae. In the generic character 

 Saccardo states that the spore is terminal, and immediately 

 beneath it is a vesicular swelling. The true explanation of 

 this is, the female cells become free from their supporting 

 hypha before conjugation, and the 'vesicular swelling' is in 

 reality the small male cell joined to the female cell by the 

 conjugating tube. This condition of things was figured by 

 Trahut and copied by myself. 



The only prevention of an epidemic is removing and 

 burning diseased plants before the resting-spores are liberated 

 in the soil. 



Magnus, Ann. Bot., n, p. 87 (1897). 

 Massee, Text-book of Plant Diseases, p. 225 (1899). 

 Saccardo and Mattirolo, Malpighia, 10 (1895). 

 Trabut, Rev. Gen. de Bot., 6, p. 409 (1894). 



Urophlyctis Riibsaameni (Magnus) forms tuberous excres- 

 cences 2-3 cm. long, on roots of Rumex scutatus in Germany. 

 Spores smooth, brown, slightly concave on one side, 40-45 /* 

 diam. 



Urophlyctis trifolii, Magnus ( = Synchytrium trifolii, Pass.) 



G 



