BOTANICAL. EVOLUTION. 469 
of leaves, so that unless they were very large it would be difficult to 
see them. One line of development then consisted in rendering these 
blossoms more‘conspicious. Of course one way of accomplishing this 
would be by the gradual enlargement of the petals, but this of course 
was what we may look upon as an expensive process, it meant the 
production of a considerable amount of comparatively unproductive 
tissue. Another and more economical.method consisted in the 
gradual reduction in size of the leaves in whose axils the flowers 
stood, and which thus became transformed into bracts. At the same 
time the internodes, i.c., the portions of stem between the leaves 
became shortened, and thus the flowers were not only individually 
more exposed to view, but became more massed together, became 
collectively more conspicuous. In this way arose those inflorescences 
or groups of flowers of which the racemes of Veronica, the panicles of 
Clematis, Rubus and Syringa (Lilac), and the little heads of Clover 
are examples. This grouping of flowers together has reached it 
maximum in Composites and their immediate allies. In these th® 
individual flowers are small, but by close aggregation they constitute 
a very conspicuous head. The outer flowers also often sacrifice them- 
selves to the common weal, Thus in the daisy and flowers like it, the 
outer row have developed their corolla to a great extent so as to make 
a show, but they have lost their stamens altogether. In the Scabious 
this differentiation is carried still further. The outer florets are 
relatively very large, but they have neither stamens nor pistil. ‘They 
are like the flags hung out by the auctioncers to announce that a sale 
is going on within. Insects come to the flower heads, and in conside- 
ration of their doing a little work in the way of carrying pollen are 
treated toa sip of honey and as much pollen as they want to eat. 
The curious part of it is, that the insects—which are the more highly 
developed of the two organisms—are unaware that they are giving a 
quid pro quo to the more lowly formed flowers in exchange for the 
sweets received by them. 
Hitherto I have spoken of most development as progressive, 7.c., 
tending towards greater differentiation. It has been shewn how- 
ever, that it is frequently just the other way. It is probable that 
the first flowers were all wind-fertilized, as is the case with all 
or nearly all existing Gymnosperms; and this was probably the 
case also with the first Angiosperms. But as we have seen, when 
insects began to visit them, a marked differentiation arose, which 
we still see going on in varying degrees of development. It may 
be that many of the flowering plants included in the Apetale 
never were insect-fertilized but have always depended on the 
wind for the conveyance of their pollen, and perhaps such 
flowers as those of the beech, willow, hazel and oak belong to 
such a primeval group. But it is equally the case, only we 
are much more certain of our ground here, that many others which 
are now anemophilous have acquired this habit as a degradation from 
the entomophilous condition. As we have seen, entomophilous flowers 
are characterized by bright colours, scent and nectar—sometimes only 
one of these attractions being present, but more frequently two or all 
three being found together. But wind-fertilized flowers are very 
different in their characters, for the wind cannot of course take any 
cognizance of those characters which appeal to the senses. They are 
