HISTORICAL DEVELOPMENT OF FLOWER POLLINATION 25 
latter gives (op. cit.), moreover, a grouping of plants according to their floral 
arrangements, and seeks to establish by statistics, the connection between floral 
mechanisms and the bodily structure of the visitors. The floral statistics begun 
by Miiller were later on extended by others, especially by Loew, MacLeod, and 
myself. 
While many investigators busied themselves with the representation of general 
floral arrangements, a still larger number investigated the mechanisms for pollination 
in individual flowers, or groups of flowers. ‘These researches, which have been 
carried out in all parts of the world, cannot possibly be even indicated here, and 
reference is therefore made to the bibliography. 
It must be the aim of research in Flower Pollination to make out the adaptations 
of all flowers and their pollinators, and this end can only be approached if such 
investigations are systematically carried on? in as many small and clearly demarcated 
areas as possible. For the attainment of this end, it is necessary that numerous 
observers should take part in the work, and that the earth should be covered with 
a net-work of stations? for the study of flower pollination. As yet, but few attempts 
have been made in this direction. In the first place there must be mentioned, 
as standing far above all other attempts, the work of Hermann Miiller (‘Alpenblumen,’ 
Leipzig, 1881), already referred to several times. It contains the observations of 
this genial and untiring author, made in the East Alps (especially in the Canton 
Graubiinden) during the years 1874-9. 
Of similar worth is MacLeod’s book, ‘ De Pyreneeénbloemen en hare bevruchting 
door insecten’ (Ghent, 1891). It contains investigations and observations in flower 
pollination made by MacLeod in the Pyrenees during the years 1889 and 1890. 
The same investigator, in his work, ‘Over de bevruchting der bloemen in het 
Kempisch gedeelte van Vlanderen’ (Ghent, 1893-4), gives an account of the floral 
arrangements of the plants of the Kempian part of Flanders, and enumerates many 
floral visitors. 
O. Kirchner in his ‘Flora von Stuttgart’ (1888) describes the floral arrange- 
ments occurring in that neighbourhood, so far as known up to his time. 
C. Verhoeff in his work, ‘Blumen und Insekten der Insel Norderney’ (Nova 
Acta d. Kais. Leop.-Carol. Deutschen Akad. der Naturf., Ixi, 1893), gives an 
exhaustive account of the mutual relations existing between flowers and insects in 
that island. 
My own memoirs on the same lines refer for the most part to the relations 
subsisting between flowers and their visitors on the islands in the German North 
Sea. A comprehensive work of this kind is ‘Blumen und Insekten auf den nord- 
friesischen Inseln’ (Kiel, 1895). This has been supplemented by my publications, 
‘Weitere Beobachtungen tiber Blumen und Insekten auf den nordfriesischen Inseln’ 
(Kiel, 1895), ‘Blumen und Insekten auf den Halligen’ (Ghent, 1894), and ‘ Blumen 
und Insekten auf der Insel Helgoland’ (Ghent, 1896). I further conducted a 
partially systematic investigation into flower pollination on the Island of Capri (1892), 
in Thuringia (1894), on the Island of Riigen (1896), and since 1877 in Eastern 
1 Cf. P. Knuth, ‘Blumen und Insekten auf den nordfriesischen Inseln,’ preface. 
2 Cf. P. Knuth, ‘Die Besucher derselben Pflanzenart in verschiedenen Gegenden,’ Part 2, 
conclusion. 
