i894. THE NATURAL HISTORY OF THE FLOWER. 349 



self-fertilisation, or to vegetative reproduction ; the number of wind- 

 fertilised plants, on the other hand, is larger in proportion than on the 

 mainland. Lastly, Macleod publishes the first instalment of a great 

 paper discussing the whole flora of West Flanders. A few new mechan- 

 isms are described, as well as many other plants which show some 

 difference in their mechanism and visitors, when compared with the 

 observations made by Miiller and others who have studied them in 

 different regions. 



The chief interest of recent work upon flowers and their insect 

 visitors seems thus to be in showing the variableness both of the 

 mechanism and of the list of visitors, and the manner in which, when 

 visitors are few, plants become more adapted to self-fertilisation, or 

 take more largely to vegetative reproduction, a point which has been 

 well brought out by Warming in his work upon flowers and insects in 

 Greenland. It is evident from this that it is desirable to study each 

 plant over a great part of its distribution area, and that it will not 

 any longer suffice to say that a plant behaves in a certain way, or 

 exhibits such and such a mechanism, without specifying where and 

 when the observations were made. By careful study of plants in this 

 manner, having regard not merely to their mechanisms for fertilisation 

 in different places, but to the size and other relations of their parts, 

 the profusion or otherwise of vegetative reproduction, the general 

 composition of the flora (which largely determines the competition 

 for insect visits), and other points, we may expect to obtain much 

 valuable information bearing on the problems of geographical botany, 

 of variation, and of evolution. It may here be pointed out that we 

 possess at present scarcely any knowledge of the British flora in this 

 direction. By a careful study of the genus Medicago in England, 

 Burkill has observed that, while the mechanism is apparently the same 

 as on the Continent, the visitors of the flower differ, and include a 

 much larger proportion of flies than are observed abroad. The same 

 worker, together with the present writer, has observed various flowers 

 in Wales, and the results (as yet unpublished) support this view of 

 the greater proportion of flies. Now this is just what Lindman and 

 Aurivillius observed in the flora of northern Europe (Norway, 

 Spitzbergen, Nova Zembla, etc.) ; hence our flora would seem rather 

 more closely allied to these northern floras in this respect than to the 

 nearer continental flora. It is to be hoped that this point may be 

 worked out more fully. 



Turning now to work in another direction, it is interesting to 

 note that the experimental study of floral phenomena is making 

 steady progress, and coming more and more into prominence. The 

 most important paper of the year is probably that of Vochting upon 

 the influence of light upon the formation and development of flowers, 

 especially cleistogamic flowers (those which never open and are' 

 necessarily self- fertilised). Plants of various kinds were grown at 

 different distances from the laboratory windows during their flowering 



