CuxgEsEMAN.—On the Fertilization of Selliera. 548 
face, and the contained pollen slowly drops into the gaping indusium im- 
mediately below. The corolla then ruptures at the back, and gradually 
opens, the five lobes, as stated above, all turning towards the front. At the 
same time the stamens elastically eurve towards the back of the flower, and 
ultimately protrude, in a withered condition, out of the posterior slit of the 
corolla. Meanwhile the lips of the indusium have closed together, thus 
firmly shutting up the pollen as if it were in a box ; and the style, instead 
of being, as before, perfectly erect, is now considerably bent down towards 
the front of the flower. It will now be noticed that the flowers are sweet- 
scented, and that a small drop of nectar always exists at the base of the 
style. 
In the meantime the stigma has been slowly growing upwards, con- 
sequently pushing before it the whole of the pollen, and ultimately forcing 
it out, bit by bit, from between the closely appressed margins of the in- 
dusium. If the pollen were to drop directly to the bottom of the flower, it 
would be impossible for fertilization to take place, but as the margins and 
sides of the indusium are furnished with a few weak hairs a portion at least 
is detained on the outside of the indusium for a time. The stigma still 
continues its growth, and when mature and ready to receive the fertilizing 
pollen protrudes considerably beyond the indusium. It is then imperfectly 
two-lobed, and is plentifully covered with rather viscid cellular papille. 
I think it will now be evident that self-fertilization cannot possibly take 
place ; for, long before the stigma reaches maturity, the pollen has been 
thrust out of the indusium ; and although, as we have seen, it may be 
detained for a time by the hairs on the outside of the latter organ, yet every 
vestige has disappeared before the stigma is in a fit condition to receive it. 
As the plant regularly produces an abundance of fruit, we are naturally led 
io the supposition that some means exist by which pollen is transferred 
from the younger flowers to the older ones. 
I have already alluded to the presence of nectar, and to the odour 
exhaled by the flowers. Can we suppose that these attributes are of no 
purpose in the economy of the plant? Hardly. There is a well-known 
axiom, that there is no effect without its cause. In this instance the cause 
of the presence of both nectar and odour is, that insects require to be 
attracted to the flowers, in order that the pollen may be regularly and 
efficiently transferred. That the attraction held out is amply sufficient, is 
proved by the fact that it is only necessary to watch the flowers for a short 
space of time, on a bright and sunshiny day, to observe that they are visited 
by numerous insects, all busily engaged in feeding upon the nectar. 
The insects are of various Orders, but I believe that fertilization is 
chiefly effected by a species of Diptera. The method pursued appears to be 
