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IOWA ACADEMY OF SCIENCE Voi.. XXVIII, 1921 
*Bidens connata (6). Pammel; Sheldahl, 1898. 
^Bidens frondosa (3) (6). 
^Bidens laevis (3). 
^Brigeron sp. According to Swingle (13) Holway reported this host at 
Decorah in July, 1884. 
^Bupatorium purpureum (3). 
^Helianthus annuus (6). 
^Helianthus doronicoides (3), (6). 
^Helianthus grosse-serratus (2), (3), (6). 
^Helianthus Maximiliani (3). 
^Helianthus tuberosus (6). 
Rudbeckia laciniata (6). Melhus; Ames, June, 1916. 
^Rudbeckia triloba (6). 
^Silphium laciniatum (6). 
^Silphium perfoliatum (6). 
^Silphium sp. Ames, July, 1909. 
^Xanthium canadense (6). 
On various members of the sunflower family. A new host reported 
in 1886. Destructive in 1902-03. “Not observed in 1894. Abundant on 
Helianthus annuus, H. tuberosum and other Composites a few years ago.” 
(8). In 1888 Halsted (10) reported that the hosts were numerous, the 
leading ones being species of Helianthus, Silphium, Eupatorium, Bidens 
and others of the Compositae. Bidens connata var. comosa was added to 
the list of hosts this year. 
Plasmopara pygmea (Ung.) Schroet. 
“On wild anemones” (1). 
Anemone canadensis. Ames, 1909. Pammel; Ames, 1910. Ames, 1911. 
Anemone dichotoma (4). 
Plasmopara Australis (Speg.) Swingle. 
Bchinocystis lobata (4). 
Plasmopara geranii (Pk.) Berl and De Toni. 
“On wild geranium” (1). 
^Geranium Carolinianum. 
^Geranium maculatum (4). Halsted (10) in 1888 reports it common 
on this host. Also states that Hitchcock found it this same year on 
Geranium Carolinianum, this making a new host for Iowa. 
P eronoplasmopara cubensis (B. and C.) Cl. 
*Mormordica balsamina (3). “Mildew of squash and cucumber, usually 
under glass” (4). 
Premia lactucae Regel. 
“On wild lettuce” (1). 
“On lettuce” (4). 
Lactuca ludoviciana (4). Hitchcock; Ames. 
Lactuca canadensis. Pammel; Ames. 
Lactuca sp. Melhus. Bessey; Ames, September, 1882. “Abundant in 
1893” (6). 
^Lactuca leucophoea. “Occasionally appeared on lower leaves of this 
host” (10). 
Prenanthes albus. Halsted (10) reports it on this host although he 
failed, to find infection in 1888. 
Peronospora obducens Schroet. 
“Wild, touch-me-nots infested” (1). 
^Impatiens pallida (3). 
. ^Impatiens biflora (10). 
Peronospora parasitica (Pers.) Tul. 
“On various crucifers” (1). 
Brassica arvensis. Hitchcock; Ames. 
^Brassica campestris (6). 
^Brassica nigra (2), (4), (6). 
