of the Genus Doassansia , Cornu. 37 
but the sorus is surrounded by a close coat of hyphae. This 
coat is often six to eight hyphae thick, and some sections 
show only cross-sections of them, while others show a confused 
mass (Fig. 84). 
The spores germinate while the sori are still in the leaf. 
The spores do not separate from the sorus, and therefore the 
promycelia and sporidia radiate out on all sides from the 
sorus. The promycelia of the inner spores force themselves 
out between the outer spores to the surface. The promycelia 
of the outer spores are about 15 /x long ; they bear, in whorls at 
their tips„ four to five slightly bent sporidia, which measure 
about i6ju in length and 3 m in diameter. I have not been 
able to learn anything farther about the development either 
of the sporidia or of the sori. 
The relationships of this species are very perplexing. It is 
in no danger of being confused with any other. From the 
species of the subgenus Doassansiopsis it is distinguished by 
the absence of a cortex, and also by having more than one 
layer of spores. From all other species it is distinguished by 
the central mass of parenchymatous cells. It certainly seems 
to belong to a distinct genus which I desire to dedicate to 
Prof. T. J. Burrill, of the State University of Illinois, who has 
done so much to advance our knowledge of American parasitic 
fungi. 
Season. The specimens were collected the last of July, 
1889. 
Distribution. Dixon, Illinois, G. P. Clinton ! The speci- 
mens were sent to Prof. Farlow by Prof. T. J. Burrill. 
Literature. 
Prof. Trelease says, on p. 36 of his Parasitic Fungi of Wisconsin 
(Trans. Wise. Acad., p. 264, Nov. 1884), that the conidia of D. 
alismatis occur upon Sagittaria. Specimens kindly sent by Prof. 
Trelease to Prof. Farlow show that the form on Sagittaria referred 
to is the present species. The ‘ conidia J were probably the sporidia 
of the sori which had germinated in position. 
