VOLUME LVI NUMBER 2 
THE 
BOTANICAL GAZETTE 
AUGUST 1913 
THE ORIGIN AND DEVELOPMENT OF THE EMBRYO 
SAC AND EMBRYO OF DENDROPHTHORA 
OPUNTIOIDES AND D. GRACILE. IF: 
HARLAN Harvey Yorxk 
(WITH SIX FIGURES AND PLATES V AND VI) 
: Introduction 
The Loranthaceae are parasitic plants that occupy a place of 
special interest among the dicotyledons. Since they are very 
peculiar, not only in their mode of life, but also in the structure of 
their reproductive organs, they have attracted much attention from 
plant morphologists. Although a considerable number of studies 
of the group have been made, their morphology and physiology are 
quite inadequately known. Our knowledge even of the European 
species of Loranthus, Arceuthobium, and Viscum, those that have 
been studied most, is as yet incomplete. . ; 
The Loranthaceae comprise more than 600 species and are 
confined largely to the tropics. Aside from the European species 
of the genera just mentioned, the development of these plants 
has been most fully studied in certain species of the same genera 
occurring in Java. In spite of the wide distribution of the genus - 
Phoradendron in the southeastern United States and the occurrence 
of scores of other species in tropical America, comparatively little 
is known of the Loranthaceae of the Western Hemisphere. 
‘Contribution from the Botanical Laboratory of the Johns Hopkins University, 
no. 26. 
89 
