406 Witson: NortH AMERICAN PERONOSPORALES 
basis ‘for the citation of Vernonia noveboracensis as a host has been 
examined and instead of that species the host is some Helianthus, 
but as the leaves seen were all very young it is impossible to 
determine the species. 
Type Locatity: Jamaica Plain, Massachusetts, on Expa- 
torium purpureum L. 
DistrisuTion: Vermont to North Dakota, California, and 
Alabama. Also in Europe. . 
Icones: FI. Nebr. 1: f/. 76. f. 5; Berlese, Icon. Fung. Phyc. 
pl. 20. 
7. Rhysotheca australis (Speg.) 
Peronospora australis Speg. Anal. Soc. Ci. Argent. 12: 36. 1881. 
Peronospora sicyicola Trel.; Farlow, Bot. Gaz. 8: $e8. 1863: 
Plasmopara australis Swing. Trans. Kan. Acad. Sci. 11: 92, 1a 
Hypophyllous, the infected area amphigenously discolored, of 
variable size and shape, bounded by leaf-veins ; conidiophores 
fasciculate, arising from the stomata of the host, 500-650 x 9- 
II, with 5-7 main branches, the branches monopodially 3-4 
times branched, the ultimate branchlets 10-14 » long; conidia 
widely ellipsoid, 14-17 x 10-13 /4; mature odspores unknown. 
This species is very distinct in habit as well as in other impor- 
_ tant characters from Pseudoperonospora cubensis, with which Euro- 
pean mycologists have sometimes confused it, The mature oospores 
are unknown, but the immature ones are described as almost hya- 
line and with a smooth epispore, 30-40 4.* 
On CucurRBITACEAE : 
Micrampelis lobata (Michx.) A. Gray, Kansas, Bartholomew 
(Fungi Columb. 2334). 
Sicyos angulatus \.., Illinois, Clinton, Pammel, Seymour 
(Econ. Fungi 42, Fungi Europ. 32766) ; Indiana, Olive, 
Wilson; Kansas, Kellerman (Fungi Europ. 32762); 
Missouri, Galloway , Nebraska, Bartholomew (Fungi 
Columb. 2556); New York, Jackson 1150, Thom; 
Ohio, Kellerman (Ohio Fungi 747); Ontario, Dearness ; 
Wisconsin, Pammel, Trelease (Fungi Gallici 3427, N. 
Am. Fungi 7476). 
Type Locatity: Recoleta, Argentina, on Cyclanthera Hystrix 
rn. 
* Swingle, 7. ¢. 
