480 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Cornu founded the genus. It is closely related to JDoassansia 
Sagittariae , having the same general appearance on its host; it has, 
however, somewhat larger spore balls, more elongated cortical cells 
and a different type of germination, which Setchell describes. Lit¬ 
erature: 23, 38, 39, 41, 160, 161. 
Doassansia opaca Setch. 
Proiomyces Sagittariae of Earl, in Bot. Gaz., 8: 276. 1883. 
Doassansia opaca Setch., Proc. Amer. Acad. Arts Sci., 26: 15. 1891. 
Exsiccati: Doassansia opaca Setch. n. sp., on Sagittaria variabilis, Rab.- 
Wint.-Paz., Eungi Ear., 3802, Seym. & Earle, Econ. Fungi Clinton Ust. 
Supp., C 12, C 13. 
Sori in leaves, forming evident opaque subcircular pustules about 
2—5 mm. in diameter and showing elevation on both surfaces of the 
leaf, more or less scattered in yellowish or reddish brown usually 
widely discolored areas; spore balls closely compacted in a single 
layer occupying most of the space between the two layers of epider¬ 
mis, consisting of a very distinct cortex and a mass of fertile cells 
entirely filling the interior, oblong to subspherical or cubical, 200— 
300 fx in greatest length; cortical cells reddish brown, oblong or 
subcubical, very prominent, about 14—27 p in length ; spores rather 
loosely compacted, chiefly subspherical, with smooth walls, 10-15 p 
in diameter. 
Host: Sagittaria variabilis , Conn., Ill., Mass, (type), R. I. 
The species is characterized by the opaque sori that show on both 
surfaces of the leaf as evident lead colored blisters. This is pro¬ 
duced by a very compact arrangement of the large spore balls which 
in cross section show as a single layer having those at the ends 
smallei and usually of triangular shape. In July, when the sori are 
young they appear as yellowish thin spots scattered over the leaf, 
but in August the spore balls begin to mature and the sori to thicken. 
The germination of the spores has not been reported. Literature * 
54, 160, 161. 
* * Doassansiopsis. 
Doassansia occulta (Hoffm.) Cornu. 
Sclerotium occultum Hoffm., Ic. Anal. Fung., 67-68, t. 16, f. 1-9. 1863. 
