No. 5.] USTILAGINEZ OF CONNECTICUT. 13 
ITI. Spores in more or less permanent balls. 
A. Forming a dusty or granular sorus at maturity. 
I. Spore balls consisting only of spores. 
a. Often evanescent (Ustilago-like spores)... 
Sorosporium. 
b. Quite permanent, adhering by folds of spore 
Oats se csvseeensew sewn Tolyposporium. 
2. Spore balls with a cortex of sterile cells...... 
Urocystis. 
B. Permanently embedded in the plant tissues. 
1. Spore balls with a definite cortex of sterile cells 
Doassansia. 
2. Spore balls without cortex but with sterile 
threads in center ................ Tracya. 
USTILAGINACEZ §Schrot. 
The sori usually form exposed, dusty, or agglutinated 
spore masses. Germination is by means of a septate pro- 
mycelium, which usually gives rise to terminal and lateral 
sporidia (capable of yeast-like multiplication in nutrient solu- 
tions), or else to infection threads. Figs. 21, 23-25. 
Ustilago Rouss. 
The sori occur on various parts of the host, according to 
the species, and at maturity form dusty, usually dark colored 
spore masses. The spores are single, separate, of small to 
medium size (5-18), and are produced irregularly in fertile 
threads that entirely disappear through gelatinization at ma- 
turity. Figs. 1-4, 43-55. : 
This is the most common and the typical genus of the 
smuts. Saccardo, in his Sylloge Fungorum, describes about 
250 species for the world: 72 species occur in North America 
and 18 in Connecticut. A number of the species possess eco- 
nomic importance as parasites of the cereals. 
Key to Species of Ustilago. 
I. Spores olive or reddish brown. 
A. Spores smooth. 
1. Sori in leaves forming linear strie.......... ‘ 
U. longissima. 
