214 A TEXTBOOK OF GENERAL BOTANY 
and appropriate one to each species. Genera are much less 
numerous than species, so it is not so difficult to get enough 
names for the genera. The use of the same specific name 
in many genera makes it much easier to find a sufficient 
number of appropriate 
names for the differ- 
ent species. 
The earliest books 
on the classification 
of plants in which 
our modern system of 
hames was used were 
written in the Latin 
language, and at the 
present time it is 
Fie. 215. Flowers of Clerodendron customary to write 

Above, presentation of stamens ; below, presenta- generic and specific 
tion of stigma, the stamens having coiled under names with Latin end- 
the petals. (x 1) ; ‘ 
ings. For this reason 
they are regarded as foreign words and so are printed in italics 
in scientific books and articles. This method has the advantage 
of making the names more prominent and shows at a glance 
what plants are discussed in any paragraph. 
POLLINATION 
Cross-pollination. Most flowers are so arranged as to facilitate 
the transfer of pollen from the stamens of one flower to the 
stigma of another (cross-pollination) rather than from the sta- 
mens to the stigma of the same flower (sedf-pollination). When 
the stamens and pistils occur in different flowers, the flowers must 
be cross-pollinated. Cross-pollination is also usual in bisexual 
flowers. One of the simplest arrangements which assures this 
is the maturing of the stigmas and anthers at different times 
(Fig. 215). The most usual agents for the transfer of pollen 
from one plant to another are insects and wind. Other agencies, 
