A Contribution to the Physiology of the 
Genus Cuscuta 1 . 
BY 
GEORGE J. PEIRCE, S.B. 
With Plate VIII. 
Introduction. 
I N the course of an investigation into the origin, develop- 
ment, and structure of the haustoria of certain parasitic 
Phanerogams, the results of which were recently published 2 , 
a number of questions presented themselves which could not 
be answered from alcohol-material, the only kind then avail- 
able. Some of the questions concerned the members of the 
genus Cuscuta, and required, for satisfactory study, consider- 
able quantities of these plants alive and in all stages of 
development. An abundance of such material was most 
generously put at my disposal by Professor W. Pfeffer, of the 
University of Leipzig, who very kindly gave me a place in his 
laboratory and helped me at all stages in my work by sugges- 
tions and criticism. The plants used were Cuscuta Epilinum , 
Weihr., cultivated on Linum usitatissimum , L . ; C. europaea , L., 
on Urtica dioica , L., and on various florists’ varieties of Chry- 
1 Diss. Inaug. at the University of Leipzig, 1894. 
2 Peirce, G. J., On the Structure of the Haustoria of some Phanerogamic Para- 
sites, Annals of Botany, vol. VII, no. XXVII, 1893. 
[Annals of Botany, Vol. VIII. No. XXIX. March, 1894.] 
