AUTHOR'S PREFACE vn 



works in Italian and French. I have, therefore, frequently been obliged to 

 content myself with information derived from references in the ' Botanischer 

 Jahresbericht' (1883 to 1895), and the 'Botanisches Centralblatt' Some 

 works had to be left altogether unnoticed, as I was not able to get any 

 information as to their contents. A few have no doubt escaped me 

 altogether, but I hope to have attained at least relative completeness. 



In course of the preparation of the material, it appeared that the 

 work would be too comprehensive for a single volume. I determined, 

 therefore, to publish in the following divisions. — 



I. Introduction and Literature. 



a. The Observations in Flower Pollination hitherto made in Europe 

 and in the Arctic regions. 



(a) Ranunculaceae to Compositae. 



{b) Lobeliaceae to Coniferae. 

 3. Observations in Flower Pollination made outside Europe. 



In the introduction, I have given, in the first place, a short survey 

 of the historical development of flower pollination. In doing this I was 

 chiefly concerned with introducing the most prominent facts in this 

 sphere of research, especially the labours of Kolreuter and Sprengel, and 

 the development of the floral theory which is associated with the names 

 of Sprengel, Knight, Darwin, Hildebrand, Axell, Delpino, and Hermann 

 Miiller. This short survey will sufficiently elucidate the present stand- 

 point of flower pollination. I was freed from the necessity of exhaustively 

 considering the historical development of this science by the excellent 

 work of E. Loew, ' Einfuhrung in die Bliitenbiologie auf historischer 

 Grundlage' (Berlin, 1895). In this work the subject is treated at great 

 length, and accordingly Loew's ' Introduction ' forms a necessary sup- 

 plement to my handbook. 



In the second division of the introduction, besides my own writings 

 and those of Hermann Miiller, I have made most use of the works of 

 Charles Darwin, F. Delpino, W. O. Focke, F. Hildebrand, A. Kerner, 

 O. Kirchner, E. Loew, F. Ludwig, H. von Mohl, Fritz Miiller, Christian 

 K. Sprengel, Aug. Schulz, and E. Warming ; and from these an idea of 

 the present position of flower pollination is obtained. The lists of self- 

 sterile, self-fertile, and cleistogamous flowers may not, however, be quite 

 complete. 



The compilation of the literature of flower pollination was made much 

 easier by the following : ' Bibliography ' in D'Arcy W. Thompson's transla- 

 tion of Hermann Miiller's ' Befruchtung der Blumen durch Insekten * 

 ('The Fertilisation of Flowers,' London, 1883, pp. 599-630), which contains 

 most references to literature up to the year 1 88a ; MacLeod's ' Lijst van 



