Johnson — Chrysophhjctis endoMotwa and other Chyiridiacece . 139 



not myself vif3ited the Irisli centres of disease. Tlie west of Ireland, which 

 has potato-troubles enough, would, I am afraid, prove ideal ground from the 

 parasite's standpoint for the spread of the potato-wart. 



I am trying the effects of soaking warty tubers in such fungicides as eor- 

 I'osive sublimate and formalin, as well as Bordeaux mixture ; but I think it 

 would be better to destroy tlie tubers outright when the tumour is obvious. 

 In some cases the tumour could be broken off by its narrow neck of attacliment 

 and the potato eaten, though even this might prove false ecouomy. Gras-lime 

 applied in May or June, and sulphur mixed with the soil, in probably non- 

 paying quantity, destroy the pest in the soil. 



Bekt-tumour, Urophlydis leproiden. 



Another Chytridian of considerable biological interest causes tumours on 

 the bulb or root of the beet' or mangel. Beta vulgaris var, ropacea, in Algiers, 

 where it was discovered in 1894 by Trabut (10), and was called by him 

 Entyloma teproides. Saccardo regarded it as a Smut, and placed it in the 

 Ustilaginaceee as CEdomyces teproides — a view supported by Prillieux and 

 others. Magnus, however, in 1897, in the "Annals of Botany," records it as 

 a Chytridian under the name of Uroplityctis teproides (11); and, curiously 

 enough, falls himself later into the error of ascribing potato-wart to it, as 

 do Massee and others. 



TJrophlyctis is an interesting genus which causes aerial galls on some 

 plants, such as clovers, TJmbelliferee, and Chenopodiacese, and root-galls on 

 others, e.g., lucerne and beet. The gall is in some a much-enlarged epidermal 

 cell, almost surrounded by many layers of other cells. In others the cavity 

 containing the spores is added to by the ramification of the original cell 

 through the gall-tissue, accompanied or not by sieve-like perforations or 

 by complete absorption of the walls of the adjoining attacked cells. Ac- 

 cording to Prillieux (12), in TJroptityctis teproides, the cavities containing the 

 spores are formed by the hollowing out of the thin-walled parenchyma, 

 forming the fleshy tumour in which the spores accumulate. It is assumed, 

 I think naturally, that Prillieux means to imply that the hollowing out is 

 due to the breaking down of the walls of the surrounding cells. Magnus 

 does not accept this view of the origin of the cavities in tlie flesh of the 

 tumour. He considers that the cavities or cysts in a swelling or lobe of a 

 tumour are all connected and derived from one original cavity or host-cell 

 which sends out, when invaded, processes. These ramify through the 

 substance of the swellings, remain in connexion with the parent cell, and 



1 The beet-tumour I examined from Co. Wexford showed no spores, and was not, as I at one time 

 thought {Jour, of Dept. of Agric, i., 1902), caused by U. leproides. The statement got into print 

 before I could suppress it. 



SCIENT. PBGC. R.D.S., VOL. XH., KG, XIV. 2 A 



