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



Setchell described this species originally from Connecticut 

 and Massachusetts. This is the only collection reported for 

 this state; the fungus is so hidden in the host that it is not 

 easily detected. 



Tracya Syd. 



The sori occur permanently embedded in the tissue of the 

 leaves (fronds). The spore balls are destitute of a cortical 

 layer, and consist of a single layer of spores enclosing a net- 

 work of septate filaments. The spores are hyaline or yellow- 

 ish, firmly united, and of small to medium size. Fig. 20. 



This genus, first described by Setchell under the name 

 Cornuella, contains a single species, which has been reported 

 only from North America and on a single species of duckweed. 

 It is closely related to Doassansia, but lacks the sterile cortex. 



Tracya Lemnae (Setch) Syd. Fig. 20. The sori occur 

 in the languishing fronds, showing the spore balls under a 

 hand lens as minute, clustered or scattered, opaque embedded 

 bodies. The spore balls are situated in the spongy paren- 

 chyma above the lower epidermis, are subspherical and rather 

 small, 50-100/i in diameter. The spores are yellowish, firmly 

 compacted, cuboidal, polyhedral or often more elongated ra- 

 dially, and chiefly 10-12/x in length; they arise from the ends 

 of the sterile network of brownish hyphse that fill the interior. 



Host and Distr. : Spirodela polyrrhiza, New Haven 

 (Setchell) ; Whitneyville, Oct., 1902. 



This is one of the most interesting species of the Ustila- 

 gineae. So far it has been reported only from four states. As 

 in Doassansia, sections of the infected tissue are necessary to 

 make out the structure of the fungus. Fig. 20 shows merely 

 a portion of the spore ball in cross section. 



LIST OF HOSTS, ACCORDING TO FAMILIES. 



MONOCOTYLS. 



Naiadace,e. Alismace.e. 



Potamogeton Pennsylvanicus. Sagittaria variabilis. 



Doassansia occulta. Doassansia deformans. 



Potamogeton sps. Doassansia obscura. 



Doassansia Martianofhana. Doassansia opaca. 



