12 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



in manure, and so fresh manure applied to corn land is apt to 

 increase the amount of smut. With onion smut we have a 

 case where the seedlings while coming through the soil are in- 

 fected by the smut established there through a previous 

 smutted crop. Onions raised from sets in this land are little 

 infected. Some success has been had in preventing this smut 

 by treating the soil with a mixture of lime and sulphur, drilled 

 into it at time of seeding. 



SYSTEMATIC TREATMENT OF CONNECTICUT 



SPECIES. 



The order Ustilagincce is divided into two families, based 

 chiefly on the method of spore germination. They are the 

 Ustilaginacecu (represented in this state by the genera Cintrac- 

 tia, Schhonella, Sorosporium, Sphacelotheca, Tolyposporium, 

 Ustilago), and the Tilletiacece (represented by Doassansia, 

 Entyloma, Neovossia, Tilletia, Tracya, Urocystis). 



Key to Genera. 



I. Spores simple. 



A. Usually forming a dusty sorus at maturity (see also 



IB and IIIAia). 

 i. Large, usually 16-35//. 



a. With an elongated hyaline appendage 



Neovossia. 



b. Without a conspicuous appendage. Tilletia. 

 2. Small to medium, usually 5-18^. 



a. Sorus covered with a false membrane of 



definite fungous cells Sphacelotheca. 



b. Protecting membrane of plant tissue only 



(sometimes with gelatinized hyphae) 



Ustilago. 



B. More or less firmly agglutinated at maturity 



Cintractia. 



C. Permanently imbedded in leaves, producing dis- 



colored areas Entyloma, 



II. Spores chiefly in pairs, forming an agglutinated sorus. . . 



Schizonella. 



