122 
PLANT STUDIES 
plants, is known as pollination, and 
the two chief agents of this transfer 
are currents of air and insects. In 
77 the transfer by currents of air 
was noted, such plants being known 
as anemophilous plants. Such plants 
seldom produce what are generally 
recognized as true flowers. All those 
seed-plants which produce more or 
less showy flowers, however, are in 
some way related to the visits of 
insects to bring about pollination, 
and are known as entomophilous 
plants. This relation between in- 
sects and flowers is so important and so extensive that it 
will be treated in a separate chapter. 
FIG. 130 A head of fruits of 
burdocK, showing the 
grappling appendages. 
After BEAL. 
