i in: ii.' »i; \ OF MJ'.i; \vk \. 



Plasmopara viticola (B. & C.) Bbbl. a DeToni id Saoo. Byll Fung VII l 

 239. 1888. 



Botrytis viticola B. & C.in Caspary Monats. BerL Acad. Mai 1855. 



Percnospora viticola Di Babi Ann. Soi. Nat. Bot. I. XX . L65. 



Sori hypophyllous, thin, effused; eonidiophores elongate 3 I times branched, 

 branches arising obliquely; sterigmata long, 5 6 . forked al i ad; conidia 

 generally three together, ovoid or oblong, 11 L5xl9 22 in diam. desti 

 tuteof papillae; oospores small, globose, 25 38 la diam.; epispore thick 

 smooth, fuscous. 



Iu leaves of Vitisriparia .' Lincoln. 



Plasmopara halstedii (Fabl.) Berl. & DeToni in Sace. Byll Puna VII l 



242. 1888. 

 Peronospora halstedii Fablow Proc. Am. Acad. Arts and Bci Will (u b X 

 65. 1883. 

 Sori thin, rounded, hypophyllous; eonidiophores rery elongate, simple to near 

 the apex, 2 3 times branched; branches shorl and thick, the Brsl arising 

 always at right angles to the stock, the others generally; oonidia ellipsoid, 

 with a conspicuous papilla, 14-16x22-25 fi\ oospores spherical, 20-30 in 

 diam , epispore yellowish, smooth. 

 In leaves of Silphium perfoliatum and S. integrifolium, Lincoln; Ambrosia 

 trifida, Wabash. PI. XVI., Fig. 5, a, b. 



4. UREMIA Kegel. Bot. Zeit. 1843, p. 665. 



Mycelium with simple haustoria; eonidiophores :; 1 times dichotomously 

 branched, the ultimate branches terminated by a disk lik<- enlargement 

 from which rise the 3-7 sterigmata; conidia with a Hat. inconspicuous 

 papilla; oospores spherical, with a thin epispore. 



Etymology: dedicated to Bremi. 



I Sir in i a lactucae Kegel 1. c, St. 39, t. III. 



Botrytis gangliformis Berk. Journ. Hort, Soc. Lond. 1.. 3L 

 Peronospora gangliformis DeBaby 1. c. 108. 



Sori thin, scattered; eonidiophores more or less arcuate, abruptly terminated 

 by a flat disk bearing several elongated sterigmata; conidia globose' 

 papilla very inconspicuous, 15 20 //; oospores spherical 25 28 s epfr 

 thin, smooth, brown. 

 In leaves of Lactuca canadensis, Lincoln. PL XVI.. Pig. 1. a, b. 



5. PEKONONI'OKA Cobda [c. Pung. 1.. 20. L837. 



Mycelium with branched filamentous haustoria; eonidiophores erect, 2 7 

 times dichotomously branched, tin' ultimate branches bearing 2 carved, 

 attenuate sterigmata; conidia ovoid or ellipsoid, without papilla), emitting 



germinating filament laterally. 

 Etymology: Greek nepovri, point, and «, seed 

 A. Oospores globose, epispore veriucosc. tuberculate or reticulate 



Peronospora artlmri Fabl. Bot. Gaz. VIII.. 315. 



Sori broadly effused, cinereous, hypophs llous; eonidiophores short, erect, 2 5 



times dichotomously branched; sterigmata elongate curved, 15 18 long; 



conidia ellipsoid or rotund, 15-18x25 27 , slightly olivaceous; 



globose, 32 12 // in diam . epispore 'lark bro« n. papillate. 

 In leaves and stems of OenotJu ra bu tints, Linooln. 



