the Ovula of Loranthus and Viscum, 73 
The fully developed embryo is oblong, clavate, the radicle forming the 
thickest part; there is a slight narrowing about the junction of the cotyle- 
dons with the radicle. In the centre of this part two oblong foveolæ or sulci 
are observable, which owe their existence to the non-union of the bases of the 
cotyledons*. The plumula is small, but totally concealed, unless indeed the 
cotyledons are cut away. The embryo is attached very slightly by a very fine 
short membrane, the originally long funiculus having disappeared.. This dis- 
appearance is, I imagine, not real; probably the tissue of the funiculus contri- 
butes to the formation of the embryo. The coloration of the embryo keeps 
pace with its development. Throughout its first stages it is colourless; the 
green colour is first visible about the time that the division of the cotyledons 
appears, and it continues increasing as the embryo approaches nearer and 
nearer to a state of perfection. 
At this time it is entirely green, the colour differing however in tint; the 
radicle, particularly towards its apex, being tinged with yellow. The greatest 
development of green is at the base of the cotyledon, about the sulci or clefts. 
With respect to the changes that have taken place at the time of maturity 
of the fruit in the calyx and ovarium, I must mention tbe total disappearance 
of green viscous tissue. The whole cellular substance between the oet 
layer, or cuticle of the calyx and the ovarium, is converted into a yellowish 
transparent viscous matter. "This is not, however, prolonged "m the stalk 
of the ovarium, which is now fibrous f. With respect to the ovarium, ue only 
remarkable circumstance is the softening down and conversion of a portion of 
its texture, particularly towards its apex, into viscous tee: This often ea 
to such a degree that the naked radicle is imbedded in the viscous tissue, "i 
is no doubt intended to remove any impediment to the occurrence of germi- 
nation. 
us Hie or three other species that I have examined me same phenomena 
occur; but in these there was no development of green viscous matter, » 
any colouring of the albumen. In one species the coty a Ba d 
dated, and two natural clefts existed; in the other, they we But inde- 
face to face, consequently no clefts were present or ERPS eee 
pendent of these, and of changes of form dependent on specific : 
Tab. V. fig. L. 
* See Tab. IV. fig. 9. t Bee 
VOL. XVIII. 
