268 Wisconsin Academy of Sciences, Arts, and Letters. 
Peronospora parasitica (Pers.) Tul. Frequent and abundant 
on various species of Cruciferae. It is probably a group of host- 
linked races. 
Peronospora potentillae DBy. Not infrequent on Agrimonia, 
Geum and Potentilla and perhaps includes three races which are 
host adapted. 
Peronospora rubi Rabh. Infrequent. Most of the collections 
were made in northern Wisconsin but in 1920 it was found along 
the railroad at Blue Mounds where leaves infected by Caeoma 
seemed to be more susceptible. One of the specimens from north¬ 
western Wisconsin is on leaves bearing Caeoma. 
Peronospora trifoliorum DBy. This is rather frequent in alfalfa 
fields but not destructive in Wisconsin. There is but a single 
specimen each on Lupinus and Astragalus in the herbarium, both 
from western Wisconsin. 
Peronospora viciae (Berk.) DBy. This occurs rather frequently 
in the pea fields but does not do much damage to the crop. 
Peronospora viciae americana Davis. Local on Yicia americana 
mostly in the western part of the state. 
Peronospora chamaesycis Wils. This is probably more frequent 
than the small number of specimens would indicate as it is not 
conspicuous. 
Peronospora floerkeae Kell. The collection made at St. Croix 
Falls by Holway in 1904 is the only one that has been made in 
Wisconsin. 
Peronospora arthuri Farl. Not infrequent on Oenothera biennis 
to which is seems to be confined. It usually shows evidence of 
systemic infection of the host. 
Peronospora alta Fckl. This is a frequent and abundant species. 
Peronospora calotheca DBy. Not frequent but sometimes locally 
abundant. All of the specimens are from the southern half of 
the state. 
Peronospora leptosperma DBy. This is a rare species in Wis¬ 
consin, being represented only from the following collections: 
Racine, 1897; Berryville, 1900; Shiocton, 1917. 
