28 
IOWA ACADEMY OF SCIENCE 
On Verbena urticifolia, L. Ames, Aug. 30, 1894 (Combs) ; Oct., 1890 
(Blaine ) ; Oct. 19, 1877 (Bessey) ; 1894 (Carver) ; Decatur Co., Sept. 3, 
1905 (Anderson) ; *Fayette, 1893 (Fink) ; Decorah, Oct., 1879 (Holway) ; 
Iowa City, Oct. 3, 1893 (Bloom). 
On Verbesina alternifolia (L.), Britt. Decatur Co., Sept., 1904 and 1905 (An- 
derson) . 
On Vernonia fasciculata, Michx. Ames, Sept. 1, 1894 (Combs) ; Sept. 12, 1894 
(Stewart) ; Iowa City, Oct. 7, 1893 (Linder). 
On Vernonia noveboracensis (L), Willd. Polk City, Aug. 29, 1902 (Pammel) ; 
Johnson Co., 1889 (Linder). 
This is our most common species of mildew, and behaves some- 
what differently on the different host plants. On Plantago major 
the mycelium is more abundant and the perithecia more numerous 
than on the similar but thinner-leaved P. rugelii. On Aster laevis 
I found asci with 2-4 spores although the species is generally easily 
recognized by its numerous 2-spored asci. During 1904 I looked in 
vain for perithecia on Verbena hastata and V. urticifolia, but found 
none although the conidial stage was very abundant. In 1905 I 
found an abundance of perithecia on both hosts. I have failed to 
find perithecia on a number of hosts supposed to be affected with 
this species and which showed conidia in abundance. Of the host 
plants here reported under this species I have found the conidial 
stage on the following in Decatur County but they are not included 
in the preceding data because no perithecia were found. Aster 
salicifolius, A. cordifolius, Carduus altissimus, Hydrophyllum vir- 
ginicum, Lappula virginica, Solidago canadensis, Verbena brae - 
teosa, Vernonia fasciculata, V. noveboracensis. Although so com- 
mon this species is not important economically. Most of the hosts 
attacked are weeds. 
3. Erysiphe galeopsidis DC. 
Erysiphe galeopsidis, DC. Fink, Blights, etc., of Fayette. 
Closely approaches E. cichoracearum, but is distinguished by its lobed 
haustoria and the absence of spores on the living host plant. 
On Mint , St. Francis river, July 14, 1897 (X). 
On Scutellaria lateriflora, L. Ames, Oct. 12, 1878 (Bessey) ; Fayette, 1893 
(Fink); Iowa City, Oct. 28, 1893 (Bloom). 
On Scutellaria galericulata Ames, 1899 (Pammel). 
On Stachys palustris, L. Ames, Oct. 5, 1898 (Ball). 
On Stachys sp. Johnson Co., X (X). 
On Teucrium canadense L. Johnson Co., X (X). 
It is very doubtful if this form is entitled to rank as a distinct 
species. It has been ascertained that certain forms of E. cichora- 
cearum do not form spores on the living host plant and that the 
