OF ARTS AND SCIENCES. 19 



certain, and even if it is one of the Uatilagincfe at all, it belongs rather 

 to the series of the pulverulent smuts, while the present form, both 

 in spore structure and in germination, is closely related to Doassansia 

 and to Entrjloma. It is to be distinguished from any of the species 

 of Doassansia by the lack of a cortex, and from any of the other 

 Eiitylomata by the presence of the central parenchymatous portion. 

 In the latter, it resembles the forms described under the subgenus 

 Doassansiopsis, but it differs from them not only In the lack of a 

 cortex but also in the possession of several layers of spores. The 

 genus is named in honor of Prof. T. J. Burrill, of the University of 

 Illinois, by whom the first specimens were sent. 



CORNUELLA, gen. nov. 



Sorus hollow at maturity, the interior containing only loose, hard- 

 ened hypha?. Spores compacted into a firm layer on the outside, 

 resembling those of Entyloma both in structure and in germination. 

 Cortex none. 



C. Lemnce, sp. nov. Spot none. Sori globular to ellipsoidal, 50-70 

 -lOOjain diameter, dark brown. Spores not separable at maturity, 

 often elongated radially, 10-12 /^ by 6-10 /x,. Promycelium some- 

 what obconical. Sporidia in whorls of 5 to 7, narrowly fusiform, 26 /x 

 by 2 yu., producing a germ tube after conjugating. 



In the fronds of Lemna (Spirodela) polyrrhiza. 



United States ! (Cambridge, Mass. !, Newton, Mass. ! ; Belchertown, 

 Mass., J. E. Humphrey !). 



The type of this genus, which I respectfully dedicate to Prof. 

 Maxime Cornu, of the Jardin des Plantes, is very different from 

 any described member of the Vstilaginece. The hollow sorus with 

 only loosely entangled hyphai on the inside, is unique, and yet the 

 spore structure and germination closely ally it with Doassansia and 

 Burrillia. 



The germination takes place while the spores are in position, and 

 the whole sorus is covered with a bristly mass of promycelia and 

 sporidia. Something of the same thing happens also in Burrillia 

 pustulata and in the species of the subgenus Doassansiopsis. 



