322 SOME SPECIAL ADAPTATIONS 
and the chances are fewer for a multiple pollination by 
wind-blown pollen. Wind-pollinated flowers are usually 
small and dull in color. 
587. On the contrary the insect (and bird): pollinated 
flowers are usually bright colored (and it has been found 
that many insects are attracted long dis- 
tances by bright colors). They are usually 
large enough to be easily visible, or if 
small are bunched in large, conspicuous 
masses (as in Elder). If not showy them- 
aes cae selves they are often bordered by showy 
leaves (as in Snow-on-the-Mountain Eu- 
phorbia marginata), or some of the flowers are con- 
verted into showy structures at the sacrifice of their 
sexual function (e.g. marginal flowers of some Dog- 
woods). In addition to these it is usual for entomophi- 
lous flowers to emit perfumes of various kinds, some 
of which are perceived by insects at great distances. 
Some of these are very unpleasant to man, but are 
attractive to certain insects, e.g. Stapelia, whose car- 
rion-like odor is attractive to carrion insects. 
588. Within the flowers are developed the secretory 
glands which secrete a sugary liquid. Attracted by 
color and odor the insects fly ito the flowers and seek out 
this nectar which they imbibe. In 
so doing they come in contact with ee 
the stamens, and become powdered (A 
with pollen, and later touch the 5.0% 09, Regular (ac- 
pistil to which the pollen is trans- Heomerphic) one Sarre 
ferred. In flowers with many 
stamens and pistils the nectaries are usually several 
in all the radii of the flower, and the insect in visiting 
will manage to become thoroughly covered with pollen 
and to put it on the summit of the stigma. In many 
