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 &xpatorium, with but few branches with the 
ganglion-like structure, and on Helianthus, where the converse is 
true. 
On AMBROSIACEAE: 
Ambrosia artemisiaefolia L., lowa, Arthur, Hitchcock ; 
Massachusetts, Farlow (N. Am. Fungi 270); Missouri, 
Demetrio ; Wisconsin, Pammel. 
Ambrosia psilostachya DC., Kansas, Bartholomew (Fungi 
Columb. 7563). 
Ambrosia trifida L., Kansas, Kellerman (N. Am. Fungi 
1403da) ; New York, Jackson 1129 ; Missouri, Pammel. 
ON CARDUACEAE? 
Bidens cernua L., Vermont, Grout. 
Bidens frondosa 1.., Alabama, Carver 173 ; Illinois, ? Fam- 
mel; Indiana, Wilson; Iowa, Arthur, Bessey, Hitch- | 
cock ; Kansas, Swingle 963; Michigan, Merrow (Econ. 
Fungi 298); Mississippi, Zracy; Nebraska, Bates 
(Fungi Columb. 2257); Ontario, Dearness ; Wiscon- 
sin, Davis, Pammel. 
Bidens laevis (1...) B. S. P., Iowa, Bessey. 
Erechtites hieractfolia (L.) 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 £. Phila- 
delphicus Willd.). 
Eupatorium ageratoides L. f., Wisconsin, Pammel. 
Eupatorium purpureum 1., Towa, Bessey (N. Am. Fungi 
209); Michigan, Merrow. 
Gnaphalium spathulatum Lam., Mississippi, Zar/e. 
Gnaphalium purpureum 1., Alabama, Atkinson (Econ. 
Fungi 374) 
Flelianthus annuus L., District of Columbia, Scribner ; 
Indiana, Arthur, Thomas; Ohio, Kellerman (Ohio 
Fungi 68, on ‘ Vitis sp.,” later corrected) ; Ontario, 
Dearness (Fungi Columb. z 32); Wisconsin, Pammel. 
Helianthus divaricatus 1. , Wisconsin, Pammel, Trelease. 
