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 /elianthus, 
but as the leaves seen were all very young it is impossible to 
determine the species. 
TYPE LOCALITY: Jamaica Plain, Massachusetts, on Eupa- 
torium purpureum L. 
DistRIBUTION: Vermont to North Dakota, California, and 
Alabama. Also in Europe. 
Icones: Fl. Nebr. 1: f/. 76. f. 5; Berlese, Icon. Fung. Phye. 
Dl. 20. 
7. Rhysotheca australis (Speg.) 
Peronospora australis Speg. Anal. Soc. Ci. Argent. 12: 36. 1881. 
Peronospora sicyicola Trel.; Farlow, Bot. Gaz. 8: 331. 1883. 
Plasmopara australis Swing. Trans. Kan. Acad. Sci. 11: 72. 1889. 
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 #2; mature oospores unknew 
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 p.* 
On CUCURBITACEAE : 
Micrampelis lobata (Michx.) A. Gray, Kansas, Bartholomew 
(Fungi Columb. 2334). 
Sicyos angulatus 1.., Ulinois, Clinton, Pammel, Seymour 
(Econ, Fungi ¢2, Fungi Europ. 32760) ; Indiana, Olive, 
Wilson; Kansas, Kellerman (Fungi Europ. 327 6a); 
Missouri, Galloway ; Nebraska, Bartholomew haa 
Columb. 2556); New York, Jackson 1150, 1) hom; 
Ohio, Kellerman (Ohio Fungi 747); Ontario, Dearness + 
Wisconsin, Pammel, Trelease (Fungi Gallici 3427, N. 
: Am. Fungi 7476). 
: oo Recoleta, Argentina, on Cyclanthera HHysiri® 
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