Witson: NortH AMERICAN PERONOSPORALES 407 
DisrripuTion: Massachusetts to Ontario, Wisconsin, Kansas, 
and Ohio. Also in South America. 
IconEs: Rep. Mass. State Agr. Exp. Sta. 8: #1. 2. f, Le. 10 = 
Rev. Myc. 22: pl. 203. f. ro, 11; Berlese. Icon. Fung. Phyc. 
6, 
8. Rhysotheca illinoensis (Farl.) 
Peronospora ulinoensis Farl. Bot. Gaz. 8: 332. 1883. 
Hypophyllous ; infected area irregular in outline, up to 10 mm., 
densely cottony, epiphyllous discoloration slight or none; conidi- 
ophores fasciculate, about 500 x 10 4, with 2-4 main branches 
which are 2-4 times laxly branched, the ultimate branchlets 10— 
12 # long, subacute ; conidia elliptic, 15-18 x &7—20 4; odspores 
unknown. 
This species is known only from the collections of Professor 
Seymour at Camp Point and Quincy, Illinois. The inconspicuous 
habit of the fungus and the wide distribution of the host make it 
very probable that the species will be found to have a much wider 
range than now known. European botanists have excluded the 
species from the genus.* Through the kindness of the authorities 
of the University of Illinois I have been permitted to examine 
material of the species. It is nearest to R. australis, but with much 
more irregularly branched and more flexuose conidiophores, which 
at first sight suggest those of Pseudoperonospora Celtidis. 
On URTICACEAE : 
Farietaria pennsylvanica L., Illinois, Seymour 5302, 5354, 
IF5S- 
TypPE LocaLity: Southern Illinois, on Parietaria pennsylvanica 
DistriBuTION : Illinois. 
9. Rhysotheca viticola (B. & C.) 
Botrytis viticola B. & C.; Berkeley, Jour. Hort. Soc. Lond. 6: 
289. 1851. (Hyponym.) 
Botrytis vitis-viticola B. & C.; Taylor, Ann. Rep. U. S. Dep. Agr. 
1871: 110. 1872. (Hyponym.) 
Peronospora viticola Caspary, Monatsb. K. Preuss. Akad. Wiss. 
1855: 331. 1855. (Hyponym); de Bary, Ann. Sci. Nat. 
iVe@O? 126, °° 5807, 
* A. Fischer ; Rabenh. Krypt. Fl. ed. 2. 4!: 485. 1892. — Berlese, Icon. Fung. 
Phyc. 41. 1898. 
