CHYTRIDIINEAE 



73 



be of great importance ; thus, for example, infection of the 

 potato by S. endobioticum has been found to be associated 

 with infection of hedge-row plants, the woody and the 

 black nightshades, Sotanum dulcamara and S. nigrum 

 respectively. 



At this point we can profitably select information on 



B r/^\\ v.; -^=rr- ii^ij'^r^ir^'^.c^ 1 f ^i rni li ft G 



FIG. 18. DETAILS OF SYNCH YTRIANS. A, young parasites in the epidermis 

 of a scabious plant ; B, a ripe parasite in its natural site ; C, the 

 typical germination of a synchytrian : the sorus formed ; D, two 

 segments of the sorus of S. globosum (of the dog-violet), showing 

 interstitial substance ; E, a sporangium of S. succisae ; F, four 

 zoospores ; G, a gall, showing the capsule of the original parasite and, 

 in the cells, stages of resting-spores. After Schroeter, reduced to f . 



that important parasite Synchytrium endobioticum, the cause 

 of wart disease or black scab of the potato. Taking first 

 information given in Leaflet No. 105 issued by the Board of 

 .Agriculture and Fisheries : " The young warts may easily 

 be seen in the eyes of the tubers. . . . They increase in size 

 and subsequently become irregular excrescences, which 



