1913] YORK—DEN DROPHTHORA QI - 
the pollen tubes, containing the “germ of the embryo,” grow down- 
ward to the embryo sacs, in which the embryos are nourished. 
He believed that the embryo sacs are formed in the “ pith of the 
peduncle” or the center of the nucellus, and that the berry is to 
be regarded as a “metamorphosed peduncle.” In conclusion, 
SCHLEIDEN states that “the Loranthaceae show, in a parasitic form, 
the intervening step between the Coniferae and more highly devel- 
oped families” of the angiosperms. MEYEN (21) held essentially 
the same views as SCHLEIDEN. 
TREVIRANUS (36) disagreed with ScHLEIDEN and MEYEN, 
believing that the central portion of the flower of Viscum album 
constitutes an ovary, within the solid tissues of which the embryo 
sacs arise. 
The investigations of HormeIsTeR (13) greatly advanced our 
knowledge of the floral organs of the Loranthaceae, he being the first 
to study the origin and development of the flowers, His extremely 
accurate observations were made on Loranthus europaeus and 
Viscum album. In these forms the flowers are axillary in origin 
and position. According to HormEIsTER, soon after the sepals 
and carpels have appeared in Loranthus the apex of the floral 
axis elongates, growing up between the carpels and forming a 
small cone-shaped mass of tissue which later becomes united with 
them. He found that the embryo sacs are formed in the elongated 
floral axis which he regarded as “a naked ovule.” Below this 
“ovule” is a little plate of collenchymatous tissue which he believed 
to be chalazal in nature. He also found that the floral parts in 
Viscum album originate quite similarly to those in Loranthus 
europaeus except that there is no swelling of the floral axis between 
the carpels, which finally fuse to form a single mass of tissue. The 
embryo sacs, which are usually two in number, arise from a group 
of cells in the tip of the floral axis. 
Van TieGHEM (37), from his observations on Viscum album, 
was led to believe that the central mass of tissue of the flower is 
apical in origin and homogeneous throughout its extent. He 
described it as being formed by two carpellary leaves, each having 
its own vascular supply from the peduncle, and becoming “connate”’ 
on their “ventral surfaces,’’ He believed that embryo sacs arise 
