4 A TEXTBOOK OF GENERAL BOTANY 
important and most conspicuous, we may for the present confine 
ourselves to a discussion of these. The typical higher plant is 
an organism with fruits, flowers, leaves, one or more stems, 
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Fig. 2. A tropical orchid (Dendro- 
hum anosmum), attached by means 
_of its roots to the trunk of a tree. 
(x) 
and roots. Fig. 1 represents these 
various parts in the case of an 
eggplant. 
Leaves. ‘he green color, which 
is due to the presence of a green 
coloring matter called chlorophyll, 
is one of the most important char- 
acteristics of. the typical higher. 
plant. Chlorophyll, in the pres- 
ence of sunlight, enables the plant 
to manufacture sugar from carbon 
dioxide (a gas found in the air) 
and water (obtained from the soil). 
The sugar is the starting point 
from which all the complex chem- 
ical compounds found in the plant 
are built. The roots of the plant 
take from the soil not only water 
but, in addition, simple chemical 
compounds which are also used in 
the elaboration of the more com- 
plex and important plant mate- 
rials. The manufacture of sugar 
from carbon dioxide and water is 
the chief function of the leaves of 
a plant. This process is known 
as photosynthesis. 
Animals do not possess chloro- 
phyll and are unable to build up 
their food substances from carbon dioxide, water, and simple 
mineral salts, but are dependent upon plants for food which has 
already been elaborated. Plants can and usually do remain in 
one place, where they absorb all the substances which they 
