Fururre Boranist. 11 
to draw the following conclusion. The flower is seldom the shape 
of an insect’s head and proboscis at rest, but it almost exactly 
includes the space occupied by its various visitors in their motions 
when visiting and sucking honey ; in other words, if we imagine 
a bee and the other insect visitors going through the same motions 
in a yielding substance like jelly, the space excavated by all the 
visitors would be an exact model of the flower. Granted the 
growth and the principle of economy, with such modifications as 
are due to the strains and mechanical support, the flower moulds 
itself, or may do so, to the average visitor. 
This gives a hint of the manner in which the shape has been 
produced (cf, a foxglove and a bumble-bee, for instance, which fit 
like an old glove to its usual finger). But this is nearly all we 
know of how flowers may have been formed. Colour, it is true, 
seems a result of strong illumination. We do know that Alpine 
flowers exposed to strong sun are much richer and deeper in colour 
than the same species when cultivated at lower levels. But far 
more observation is required to shew even this properly. It is 
particularly important to know whether such flowers as the rose, 
_bramble, anemone, &c., are more often pink when growing in 
sunny localities; and this is one question for the future British 
botanist. Another point for his attention is the size and number 
of flowers. I can, without hesitation, say that in exposed situa- 
tions the number of flowers is usually greater than in sheltered 
places, and their size is, I think, usually diminished, but this point 
ought to be investigated with proper measurements. Another 
effect of strong exposure is to shorten the pedicels, which are more 
or less directly suppressed by the transpiration in exposed places. 
The result is to aggregate the flowers into a head or close corymb. 
In the colour, size, number, and the aggregation of flowers into 
heads or corymbs, therefore, the effect of exposure may be directly 
traced, and in the future these points will, no doubt, be proved. 
If we turn to the vegetative system, the first point to notice 
is the shape of leaves. Of course leaves exist in order that the 
plant may obtain as much light and carbonic acid as is possible 
without hurting the tissue. It follows that there are two points 
to observe. The first is the manner in which the shapes of leaves 
and their positions on the branch are so arranged that they take 
up as much as possible of the light which falls on them. In the 
summer I could have shewn you any number of examples, but at 
