404 Witson: NortH AMERICAN PERONOSPORALES 
exhaustive study of a much greater quantity of material, both 
conidial and odsporic, is possible than is at present at hand, seg- 
regation of this species had best not be attempted. The extreme 
forms are found on Expatorium, with but few branches with the 
ganglion-like structure, and on He/ianthus, where the converse is 
true. 
On AMBROSIACEAE : 
Ambrosia artemisiacfolia L., Iowa, Arthur, Hitchcock ; 
Massachusetts, Farlow (N. Am. Fungi 270) ; Missouri, 
Demetrio; Wisconsin, Paimmel. 
Ambrosia psilostachya DC., Kansas, Bartholomew (Fungi 
Columb. 7563). 
Ambrosia trifida L., Kansas, Kellerman (N. Am. Fungi 
1403a); New York, Jackson 1129 ; Missouri, Pammel. 
On CaRDUACEAE ? 
bidens cernua L.., Vermont, Grout. 
Bidens frondosa \.., Alabama, Carver 173 ; Mlinois, ? Fam- 
mel; Indiana, Wilson; Iowa, Arthur, Bessey, Hitch- 
cock ; Kansas, Swingle 963 ; Michigan, Merrow (Econ. 
Fungi 298); Mississippi, Tracy; Nebraska, Bates 
(Fungi Columb. 2257); Ontario, Dearness ; Wiscon- 
sin, Davis, Pammel. 
Bidens laevis (L.) B. S. P., lowa, Bessey. 
Erechtites hieractfolia (1...) Raf., Illinois, Waite ; New Jersey, 
Halsted (Econ. Fungi 308 a); Massachusetts, coll. ign. 
(Econ. Fungi 308 6); Wisconsin, Davis. 
Erigeron annuus (L.) Pers., Wisconsin, Davis (as E. Phila- 
delphicus Willd.). 
Eupatorium ageratoides L. f., Wisconsin, Pammel. : 
Eupatorium purpureum L., lowa, Bessey (N. Am. Fung! 
209); Michigan, Merrow. 
Guaphalium spathulatum Lam., Mississippi, Ear/e. 
Guaphalium purpureum L., Alabama, Atkinson (Econ. 
Fungi 374). 
Flelianthus annuus L., District of Columbia, Scrtbmer+ 
Indiana, Arthur, Thomas; Ohio, Kellerman (Ohio 
Fungi 68, on “ Vitis sp.,” later corrected) ; Ontarlo, 
_ Dearness (Fungi Columb. 132); Wisconsin, Pammel. 
Helianthus divaricatus L., Wisconsin, Pammel, Trelease- 
