392 Witrson: Norru AMERICAN PERONOSPORALES 
northern than in the southern states, as it requires a cool, moist 
atmosphere in which to develop to the best advantage. Besides 
- the potato, which is its chief host, the fungus attacks numerous 
other species of the genus So/anum as well as members of various 
other genera of So/anaceae. 
ON SOLANACEAE: 
Solanum tuberosum ., Connecticut, Clinton (Fungi Co- 
lumb. 7839); Illinois, Burrill, Seymour (N. Am. Fungi 
2204); lowa, Blackwood, Buchanan, Holway, Pammel ; 
New York, Z/iis (F ungi Carol. 5: 92), Whetzel; Ten- 
nessee, Scribner (Econ. Fungi 447); Vermont, Jones ; 
Wisconsin, Pammel, Trelease. 
Lycopersicon Lycopersicon (L.) Karst., Delaware, Smith 
(Fungi Columb. 2738); South Carolina, Ravenel (Myc. 
Univ. 926). 
Type LocaLity: F rance, on Solanum tuberosum 1. 
Distripution: Eastern Canada to California and Florida. 
Also in South America, Europe, Asia, Africa, and Australia. 
Icones: Bot. Zeit. 5: pl. 6. f, z-6 ; Bull. Bussey Inst. 1: 
319. fig.; Bull. Ill. Lab. Nat. Hist. r'- pl. 2. f. 810 ; Frank, 
Lehrb. Bot. 2: 114. f. 327; Rep. U.S. Dep. Agr. 1888: Veg. 
Path. pl. 1, 2; Rep. Maine Agr. Exp. Sta. 1889: 172. f. 2-10; 
Rep. Vt. Agr. Exp. Sta. 1890: 1 32. fig.; Rep. N. J. Board Agr. 
17: pl. 4; v. Tubeuf, Pflanzenkrankheiten 142. f. 37, Bull. Calif- 
Agr. Exp. Sta. 175: f. 3, 6-8 ; Berlese, Icon. Fung. Phyc. f/. 8. 
6. Phytophthora Thalictri Wilson & Davis 
Hypophyllous, the infested area suborbicular or irregular in 
outline, appearing somewhat 
not forming a dense felt, 300-400 X 5-7 w, bearing usually 1 or 2 
‘hes, subconidial swellings narrowly conical, less than twice 
as thick as the branch ; conidia elliptic, apically papillate, 20-27 
.*% 13-17 #; oOspores unknown. 
Type collected by Dr. J. J. Davis, June 20, 1907, in Kenosha 
County, Wisconsin, on Thalictrum purpurascens L., 
Distinguished from P. infestans by the more pronounced dis- 
