_ BoranicaL GAZETTE. 
Von. IX. MARCH, 1884, No. 3. 
— Uae 
Additions to the Peronosporex of the United States. 
BY W. G. FARLOW. 
With the species received from them. The numbers given are 
those affixed to the species in the Hnumeration, and additional 
1. P. viticola, 
The form on Ampelopsis quinquefolia was also found in September, 1883, at 
Ithaca, Wis., Prof. Wm. Trelease. It appears from a review in Just, which I 
have just seen, that Pirrota, in a paper published in Milan, 1880, stated that 
- viticola occurs on species of Cissus and Ampelopsis in Italy. I have not seen 
the original paper of Pirrota, and its contents are only known to me irom the 
teview above named. . 
2. P. Halstedii. 
Occurs on the following additional hosts: Hupatoriwn ageratoides, Wiscon- 
Sin, Trelease ; Silphium perfoliatum and S. laciniatum, Towa, Profs. Bessey and 
ne Arthur; Bidens chrysanthemoides, Cambridge. 
4. P. Geranii. : 
e form on G. Carolinianum, found by Mr. Earle, seems to belong to this 
Species without doubt. Specimens collected in April show a large proportion 
of the monstrous conidia, others collected later, in May, show a smaller propor- 
Hon of the large conidia, and in specimens on the same host collected by Mr. C. 
A. Hart in J uly the conidia are the same as in the normal form of P. Geranii. 
- } parasitica. 
Also on Draba Caroliniana and Lepidium intermedium, Iowa, Arthur, 
10. P. Potentitie. 
On P. Norvegica, Minois, C. A. Hart. 
