UROCYSTIS 



349 



is recommended that onions should be transplanted, because 

 at a certain age the plants cannot be infected, even if spores 

 are in the ground. Diseased plants should be collected 

 when thinning is in operation. 



Thaxter, Ann. Rep. Conn. Expt. Stat., p. 129 (1890). 







tt 



4 * 



FIG. 105. Urocystis colchici. i, portion of infected leaf ; 2, a 

 single sorus, slightly mag. ; 3, spores, highly mag. 



Colchicium smut (Urocystis colchiti, Rab.) forms long 

 rows of black, powdery streaks on the leaves of colchicum 

 Colchicum autumnale, Muscari racemosum, M. comosum, 

 Stilla bifolia, Allium rotundum, A. cepa^ A. magicum, and 

 Paris quadrifolia. 



Spore-clusters globose or oblong, 20-33X16-20^; central 

 fertile spores chestnut-brown, sterile peripheral cells pale 

 yellowish-brown, small. 



Gladiolus smut (Urocystis gladioli, Smith) sometimes 

 attacks the corms of cultivated kinds of Gladiolus in this 

 country. The spore-balls average 40-50 p diam. The 

 central fertile spores are dark brown, angularly globose, 

 smooth, 4-6 /A diam., sterile peripheral cells numerous, pale. 



Destroy infected corms, as cure is out of question. 



