CHAPTER XL 



ONION SMUT. 



Urocystis cepulce, Far. 



IN 1879 a disease of onions appeared in France, known 

 as the " American Onion Smut," Urocystis cepulce, Farlow, 

 a disease which had hitherto "been confined to America. 

 Fungi belonging to Urocystis are parasitic on living plants, 

 and familiar allies in this country are the bunt of wheat, 

 Tilletia caries, Tul. ; corn smut, Ustilago carlo, Tul. ; the 

 common black smuts of violets and colchicum, named 

 Urocystis violoe, B. and Br., and U. colchici, Tul. ; potato 

 smut, Tubercinia scabies, B. and Br., and many others. 

 It is probable that we already have this disease in Britain, 

 as onion growers have sorely complained of late of their 

 onions falling into a dusty black mass after harvesting. 

 Whether this fungus is really distinct from the common 

 smut of colchicum, U. colchici, Tul., seems somewhat un- 

 certain. The name of the parasite is derived from uro 

 to burn, Jcystis a bladder, and ccepa the onion plant. 



