XI 
THE SPECIAL COLOURS OF PLANTS 
319 
Crista-galli); while in drier meadows we have cowslips, 
ox-eye daisies, and buttercups, all very distinct both in form 
and colour. So in cornfields we have the scarlet poppies, the 
purple corn-cockle, the yellow corn-marygold, and the blue 
cornflower; while on our moors the purple heath and the 
dwarf gorse make a gorgeous contrast. Thus the difference 
of colour which enables the insect to visit with rapidity and 
unerring aim a number of flowers of the same kind in suc¬ 
cession, serves to adorn our meadows, banks, woods, and 
heaths with a charming variety of floral colour and form at 
each season of the year. 1 
Fertilisation of Flowers by Finis. 
In the temperate regions of the Northern Hemisphere, 
insects are the chief agents in cross-fertilisation when this is 
not effected by the wind : but in warmer regions, and in the 
Southern hemisphere, birds are found to take a considerable 
part in the operation, and have in many cases led to modifi¬ 
cations in the form and colour of flowers. Each part of the 
globe has special groups of birds which are flower-haunters. 
America has the humming-birds (Troehilkke), and the smaller 
group of the sugar-birds (Caerebidse). In the Eastern tropics 
the sun-birds (Nectarineidae) take the place of the humming¬ 
birds, and another small group, the flower-peckers (Dicaeidas), 
assist them. In the Australian region there are also two 
flower-feeding groups, the Meliphagida?, or honey-suckers, 
and the brush -tongued lories (Trichoglossidae). Recent re¬ 
searches by American naturalists have shown that many 
flowers are fertilised by humming-birds, such as passion¬ 
flowers, trumpet-flowers, fuchsias, and lobelias ■ tvhile some, 
as the Salvia splendens of Mexico, are specially adapted to 
their visits. We may thus perhaps explain the number of 
very large tubular flowers in the tropics, such as the huge 
brugmansias and bignonias; while in the Andes and in 
1 This peculiarity of local distribution of colour in flowers may be com¬ 
pared, as regards its purpose, with the recognition colours of animals. Just 
as these latter colours enable the sexes to recognise each other, and thus avoid 
sterile unions of distinct species, so the distinctive form and colour of each 
.species of flower, as compared with those that usually grow around it, enables 
the fertilising insects to avoid carrying the pollen of one flower to the stigma 
of a distinct sj^ecies. 
