On the Fertilization of Peronospora 
parasitica. 
BY 
HAROLD WAGER. 
With Plate XVI. 
INCE the classical researches of De Bary upon the 
phenomena of fertilization in the Peronosporeae 1 , the 
subject has been studied by Marshall Ward 2 , Fisch 3 , Chmie- 
lewsky 4 , Istvanffi 5 , Dangeard 6 , Berlese 7 , Stevens 8 , and 
myself. 
The investigations of De Bary and Marshall Ward definitely 
established the fact that certain genera of the Peronosporeae 
exhibited some of the phenomena of fertilization in the fusion 
of protoplasmic masses derived from male and female cells, 
1 See Comp. Morph. &c., of Fungi, Eng. Ed. 
2 Observations on the genus Pythium. Q. J. M. S., xxiii, 1893. 
3 Ueber das Verhalten der Zellkeme in fusionierenden Pilzzellen. See Bot. 
Cent, xxiv, p. 221. 
4 Zur Frage liber die Copulation der Kerne beim Geschlechtsprocess der Pilze, 
See Bot. Cent, xxxviii, p. 689. 
5 Ueber die Rolle der Zellkerne bei der Entwicklung der Pilze. Ber. d. deut. 
Bot. Gesell. xiii, 1895, p. 456. 
6 Recherches sur la Reproduction sexuelle des Champignons. Le Botaniste, 
1894, p. 221. 
7 Ueber die Befruchtung und Entwickelung der Oosphare bei den Peronosporeem 
Jahr. f. wiss. Bot. xxxi, p. 159. 
8 The compound Oosphere of Albugo Bliti. Bot. Gaz. xxviii, 1899. 
[Annals of Botany, Vol, XIV, No. LIV. June, 1900.] 
