viii PREFATORY NOTICE. 
Hermann Miiller has by no means confined his attention to the 
manner in which pollen is carried by insects or other animals 
from plant to plant, for wind-fertilised flowers have been carefully 
described by him; and several curious transitions from the one 
state to the other are noticed. He has also attended more closely 
than any one else to the many contrivances for self-fertilisation, 
which sometimes co-exist with adaptations for cross-fertilisation. 
For instance, he has discovered the singular fact that with certain 
species two kinds of plants are regularly produced, one bearing 
inconspicuous flowers fitted for self-fertilisation, and the other kind 
with much more conspicuous flowers fitted for cross-fertilisation. 
The flowers on the first-mentioned plants serve the same end as 
the curious little closed cleistogamic flowers which are borne by a 
considerable number of plants, as described and enumerated in the 
present work. 
There is another interesting feature in the Befruchtung, by 
which it differs from all other works on the same subject; for it 
includes not only an account of the adaptation of flowers to insects, 
but of different insects to differently constructed flowers for the 
sake of obtaining their nectar and pollen. 
Any one who will carefully study the present work and then 
observe for himself, will be sure to make some interesting dis- 
coveries; and as the references to all that has been observed are 
so complete, he will be saved the disappointment of finding that 
which he thought was new was an already well-known fact. I 
may perhaps be permitted here to mention a few points which 
seem to me worthy of further investigation. There are many 
inconspicuous flowers which during the day are rarely or never visited 
by insects, and the natural inference seems to be that they must 
be invariably self-fertilised ; for instance, this is the case with some 
species of Trifolium and Fumaria which bear very small flowers, 
with some species of Galium, Linum catharticum, &. Many other 
such flowers are enumerated by Miiller. Now it is highly desirable 
_that it should be ascertained whether or not these flowers are 
4 
‘a 
| 
j 
uf 
3 
| 
