224 



PLANT DISEASES 



not be sown for some years. The disease appeared in one 

 instance after a period of twelve years' rest, due presumably 

 to smut-spores still present in the soil. 



Thaxter, Ann. Rep. Conn. Agric. Expt. Station, p. 129, 

 pi. 2 (1890). 



Weed, Fungi and Fungicides, p. 152. 



COLOHICUM SMUT 



(Urocystis colchici, Rab.) 



This smut often forms long rows of black, powdery 

 streaks on the leaves of Colchicum (Cokhicum autumnale), 



Fig. 54. Urocystis colchici. i, Portion of a diseased leaf, 

 nat. size ; 2, a single sorus, slightly mag. ; 3, spores, x 300. 



Muscari racemosum, M, comosum, Scilla bifolia. Allium 

 rotundum, A. cepa, A. magicum, and Paris quadrifolia. 



