Johnson . — On Arceutkobium Oxycedri . 141 
pollination and fertilisation. The occurrence, however, of a 
similar long interval in Viscum album growing on the apple 
which shows no such interval does not give much countenance 
to this view. 
Before attempting to assign to the ovarian papilla and its 
two embryo-sacs their morphological values it will be well to 
consider the condition of the ovary as seen in Arceutkobium 
and other Loranthaceae (Eulorantheae and Visceae of the 
Genera Plantarum) by different observers. 
1. Arceuthobium. 
Professor Oliver 1 was the first, in 1870, to notice a papilla 
in the ovary of Arceuthobium, the species being A. cryptopodum. 
I cannot do better than quote his remarks : — ‘ From the 
material at my disposal I cannot at present satisfactorily 
explain the nature of the ovuliform body. It may be a 
fertilised embryo-sac the lower portion of which is so engaged 
in its early stage in the subjacent cellular tissue as to appear 
to be in continuous connection with it. In this case the 
minute enclosed sac bounded by a free but well-defined 
membranous wall and full of more or less distinct definite 
cells must represent an early condition of development of the 
embryo in the embryo-vesicle, although its occurrence thus, 
as a minute spherical sac without trace of suspensor near the 
apex of an embryo-sac already filled with cellular tissue, 
appears to be at variance with the usual mode of its formation 
in Loranthaceae. 
c On the other hand, the papilla [figures 8 and 9 in leones] 
looks at first sight much like a naked free ovule, and the 
enclosed vesicle [figure 10 in leones] an embryo-sac filled 
with cellular tissue. Against this apparently reasonable view 
is the circumstance that at the stage represented by figure 9 
[in the leones], or rather later, the entire body exhibits a ten- 
dency to separate on pressure by a clear line at the base from 
the tissue beneath. We have not, moreover, any case that I am 
aware of in Loranthaceae, in which the ovule is wholly free. 
1 D. Oliver, in Hooker’s leones Plantarum, 1870, t. 1037. 
