raordinary that I have ever read, and I am glad
you are going to publish it. I have long wished some one to observe the
fertilisation of Scaevola, and you must permit me to tell you what I
have observed. First, for the allied genus of Leschenaultia: utterly
disbelieving that it fertilises itself, I introduced a camel-hair brush
into the flower in the same way as a bee would enter, and I found that
the flowers were thus fertilised, which never otherwise happens; I then
searched for the stigma, and found it outside the indusium with the
pollen-tubes penetrating it; and I convinced Dr. Hooker that botanists
were quite wrong in supposing that the stigma lay inside the indusium.
In Scaevola microcarpa the structure is very different, for the immature
stigma lies at the base within the indusium, and as the stigma grows it
pushes the pollen out of the indusium, and it then clings to the hairs
which fringe the tips of the indusium; and when an insect enters the
flower, the pollen (as I have seen) is swept from these long hairs on to
the insect's back. The stigma continues to grow, but is not apparently
ready for impregnation until it is developed into two long protruding
horns, at which period all the pollen has been pushed out of the
indusium. But my observations are here at fault, for I did not observe
the penetration of the pollen-tubes. The case is almost parallel with
that of Lobelia. Now, I hope you will get two plants of Scaevola, and
protect one from insects, leaving the other uncovered, and observe the
results, both in the number of capsules produced, and in the average
number of seeds in each. It would be well to fertilise half a dozen
flowers under the net, to prove that the cover is not injurious to
fertility.

With respect to your case of Aristolochia, I think further observation
would convince you that it is not fertilised only by larvae, for in a
nearly parallel case of an Arum and a Aristolochia, I found that insects
flew from flower to flower. I would suggest to you to observe any cases
of flowers which catch insects by their probosces, as occurs with
some of the Apocyneae (593/1. Probably Asclepiadeae. See H. Muller,
"Fertilisation of Flowers," page 396.); I have never been able to
conceive for what purpose (if any) this is effected; at the same time,
if I tempt you to neglect your zoological work for these miscellaneous
observations I shall be guilty of a great crime.

To return for a moment to the indusium: