vanced the biology of flowers beyond
the initial stage, we cannot be surprised that other botanists followed
to even a less extent the lines laid down by Kolreuter and Sprengel.
This was in part the result of Sprengel's supernatural teleology and in
part due to the fact that his book appeared at a time when other lines
of inquiry exerted a dominating influence.

At the hands of Linnaeus systematic botany reached a vigorous
development, and at the beginning of the nineteenth century the anatomy
and physiology of plants grew from small beginnings to a flourishing
branch of science. Those who concerned themselves with flowers
endeavoured to investigate their development and structure or the most
minute phenomena connected with fertilisation and the formation of the
embryo. No room was left for the extension of the biology of flowers on
the lines marked out by Kolreuter and Sprengel. Darwin was the first to
give new life and a deeper significance to this subject, chiefly
because he took as his starting-point the above-mentioned problems, the
importance of which is at once admitted by all naturalists.

The further development of floral biology by Darwin is in the first
place closely connected with the book on the fertilisation of Orchids.
It is noteworthy that the title includes the sentence,--"and on the good
effects of intercrossing."

The purpose of the book is clearly stated in the introduction:--"The
object of the following work is to show that the contrivances by which
Orchids are fertilised, are as varied and almost as perfect as any of
the most beautiful adaptations in the animal kingdom; and, secondly,
to show that these contrivances have for their main object the
fertilisation of each flower by the pollen of another flower."
("Fertilisation of Orchids", page 1.) Orchids constituted a particularly
suitable family for such researches. Their flowers exhibit a striking
wealth of forms; the question, therefore, whether the great variety
in floral structure bears any relation to fertilisation (In the older
botanical literature the word fertilisation is usually employed in cases
where POLLINATION is really in question: as Darwin used it in this sense
it is so used here.) must in this case possess special interest.

Darwin succeeded in showing that in most of the orchids examined
self-fertilisation is either an impossibility, or, under natural
conditions, occurs only exceptionally. On the other hand these plants
presen