1900] THE HAUSTORIA OF THE ERYSIPHEZ 181 
represented, though it may have been a tube of Phyllactinia. 
Whether or not Sphzrotheca has a similar habit to Uncinula, I 
have not determined. 
It is a pleasure to acknowledge the assistance I have had in 
this investigation from Professor C. R. Barnes, under whom the 
work was begun, and from Professor R. A. Harper, under whom 
it was mainly accomplished. 
BELOIT COLLEGE, 
eloit, Wis. 
LIST OF GENERA AND SPECIES STUDIED. 
Erysiphe communis (Wallr.) on Geranium maculatum L. 
graminis DC. on Poa pratensis L. 
Galeopsidis DC. on Scutellaria laterifiora L. 
Galeopsidis DC. on Galeopsis Tetrahit L. 
communis on Polygonum aviculare L. 
oracearum DC. on Eupatorium perfoliatum L. 
Podosphera Oxycanthe DC. on Prunus sp. 
Microsphera Russellii Clinton on Oxalis corniculata stricta Sav. 
Uncinula Salicis DC. Wint. on Salix discolor Muhl. 
necator Schw. on Vitis sp.? 
———. Clintonii Peck, on Tilia Americana L. 
Phyllactinia suffulta (Reb.)* on Fraxinus pubescens Lam.; Crategus punc- 
tata Jacq.; Xanthoxylum Americana Mill; Corylus Americanum Walt; 
Cornus stolonifera Michx. 
Such forms as are not discussed in the preceding pages have not been 
found to differ so materially from Erysiphe communis as to require a separate 
discussion of their haustoria. 
BIBLIOGRAPHY. 
1, AMICI: Attidel’Accad. dé Georgofili di Firenzi 30:—. —Monitore Toccano, 
Aug. 1, 1853.—Gard. Chron. 1853 : 580.— London Hort. Soc. 8: 231. 
BERKELEY: Gardeners’ Chronicle 1846 : 269. 
~————: Gardeners’ Chronicle 1847 : 779- 
———.: Gardeners’ Chronicle 1854 : 805 ; 
————.: Gardeners’ Chronicle 1856 : 564. 
: Gardeners’ Chronicle 1856 : 485 ; 1857 : 580. 
"The material has not been examined with reference to the classification 
lactinia proposed by Palla (24, p. 65). 
1856: 485 ; 1857: 199- 
anes 
of Phyl- 
