of the Genus Doassansia , Cornu. 
43 
Systematic Arrangement. 
Genus I. Doassansia, Cornu. Sorus, a mass of spores 
surrounded by a distinct cortex of parenchymatous cells 
[Eudoassansia) ; or with the central portion composed of fine 
hyphae [P seudo doassansia) ; or of a mass of cellular tissue 
(Doassansiopsis ) . 
Subgenus I. Eudoassansia . The body of the sorus con- 
sisting entirely of spores which at maturity are readily 
separable from one another. Cortex well developed. 
1. D. epilobii , Farlow. 
2. D. hottoniae (Rostr.), De Toni. 
3. D. sagittariae (Westend.), Fisch. 
4. D. opaca , sp. n. Spot circular, slightly swollen on both surfaces, 
lemon-yellow. Sori indistinct, more or less cubical, crowded 
together, 200-300 n by 80-100 p. Spores nearly spherical, 
10-15 i n diameter. Cells of the cortex irregular in shape, form 
nearly cubical to brick-shaped. 
The leaves of Sagittaria variabilis. 
Newton, Mass., Prof. W. G. Farlow ! Medford, Mass.! 
Norwich, Conn. ! 
5. D. alismatis (Nees), Cornu. 
Subgenus 2. Pseudodoassansia. Central portion of the 
sorus composed of fine hyphae. Spores in irregular layers 
separable at maturity. Cortex very distinct. 
6. D. obscura , sp. n. Spot light-yellow and indistinct, or none. Sori 
in vertical lines in the larger intercellular spaces, 150-300 n in 
diameter, nearly globular. Spores loosely packed together, 
8-12 fx in diameter. Cells of the cortex obconical, with the 
outer, broad end more or less deeply lobed ; light-brown. Pro- 
mycelium cylindrical, about 20 p long. Sporidia in a whorl of 
5-7, 16-17 p long by 1 ‘5-2 fi thick, producing secondary 
sporidia without conjugation. 
On petioles and peduncles of Sagittaria variabilis. 
Norwich, Conn. ! Medford and Cambridge, Mass. ! 
