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part 1] HISTORICAL INTRODUCTION. 17 
My brother, Fritz Miiller,has made many interesting observations 
on South Brazilian plants, in all the three lines of research which 
Darwin instituted. His results have been contributed partly to 
the Jenaische Zeitschrift and Botanische Zeitung, partly to Darwin’s 
Variation of Animals, ete., and are partly published for the first 
time in this book. He has found in the case of various orchids 
that they are not only sterile to their own pollen, but even that 
the pollen and stigma of the same flower act as fatal poisons to 
-one another. In various flowers (Chamissoa, Epidendrum) he has 
discovered special contrivances in the act of being evolved, and 
especially in Posoqueria and Faramea he has given clear proof 
that certain peculiarities, advantageous under the given conditions, 
have by no means attained their full perfection. The proof of this 
fact deserves special attention as a strong objection to the teleolo- 
gical theory. His comprehensive observations on Brazilian orchids 
will; it may be hoped, soon be published in a special work. 
Severin Axell published in 1869 a book on the floral mechanisms 
of Phanerogams. It contains a clear historical review of the growth 
of our knowledge of the sexual relations of plants, and describes 
some new investigations of floral mechanisms and some experiments 
on the fertility of plants after self-fertilisation, It is remarkable 
for divesting of a certain onesidedness the conception that had 
flowers are adapted for cross-fertilisation by animals are fully treated and very clearly 
arranged. He distinguishes :— 
1, Adaptations which affect the senses of sight and smell in the fertilising 
agents. 
(a) Colour, 
(b) Scent. 
2. Adaptations which affect the sense of taste: the attractions of pollen, honey, 
aud other food-materials. : 
3. Arrangements which direct the actions of the fertilising agents, and make 
them more effective. 
(a) Increase of conspicuousness by heliotropy, the position and grouping 
of the flowers, enlargement of particular organs, ete. 
()) The development of certain parts convenient for alighting on or 
standing on. 
(c) Arrangements for preserving the nectar for the use of the fertilising 
agelts, 
(d) ce teuiante for promoting the transfer of pollen from the anthers 
to the body of the fertilising agent, and thence to the stigmas. 
(ec) Arrangements for ensuring the transport of pollen from one flower to 
another, or from one individual plant to another, 
(f) Arrangements for regulating the number of visits of the fertilisin 
agents. ; 
(g) Arrangements for adapting the flowers to particular fertilising agents 
ey 
o 
Finally, Delpino gives a classification of flowers according to their different types, 
of which he distinguishes forty-seven, and he appends some remarks on the fertilising 
agents of plants and their habits. 
C 
