Witson: NortH AMERICAN PERONOSPORALES 75 
description.’”’ As the latter is too vague to allow of a more definite 
determination than would the mere citation of the host, this species 
had probably best be placed with the present one. The morph- 
ology of this species has been studied by Stevens.* 
On AMBROSIACEAE: 
Ambrosia artemisiacfolia L., Alabama, *Carver z8o ; Illinois, 
*Hart,; Kansas, *Swingle 1667 ; Massachusetts, */ar/ow 
(N. Am. Fungi 2056), *Seymour ; Missouri, *Demetrio (N. 
Am. Fungi 2427); New Jersey, *Halsted (Econ. Fungi 
291a), Stevens; New York, Underwood; South Dakota, 
Chaney, Williams (Econ. Fungi 2976); Wisconsin, Pam- 
mel, 
Ambrosia psilostachya DC., lowa, *Macbride ; South Dakota, 
Rydberg 798 ; Utah, Macbride. 
Ambrosia trifida L., Kansas, Swingle. 
Gaertneria acanthocarpa (Hook.) Britton, Utah, * Garrett (Fungi 
Columb. 2205). 
Iva ambrosiaefolia A. Gray, Arizona, *Griffiths (W. Am. Fungi 
336, on “ Franseria tenuifolia Gray”’); New Mexico, Tracy 
8To. 
Iva ciliata Willd., Ilinois, *Hart; Missouri, * Hart. 
On CARDUACEAE: . 
Artemisia biennis Willd., Montana, Anderson & Kelsey. 
Carduus arvensis (L.) Robins., New York, Arthur, Brown, 
* Halsted (Econ. Fungi 302), Stevens, Underwood ; Ontario, 
Dearness. 
Carduus lanceolatus L., Newfoundland, ? Waghorne. 
Carduus muticus (Michx.) Pers., Minnesota, Holway 241; 
Ontario, Dearness. 
Carduus spinosissimus Walt., Louisiana, *Zanglots 3 5. 
Matricaria matricarioides (Less.) Porter, California, *Adrams 
2487, Oregon, *Lloyd. 
Parthenium integrifolium L., lowa, * Arthur. 
Parthenium repens Eggert, Kansas, Hitchcock 1086. 
? Senecio cymbalaroides Nutt., Montana, Kelsey. 
Senecio Hartianus Heller, Colorado, Rydberg & Vreeland 5499. 
* Bot. Gaz. 32: 85, 97, 259. pu 3s Pl. tS 43 53+ 190% 
