22 THE VEGETABLE WORLD. 
which each plant has to take in the vast vegetable population which 
covers and adorns the globe. Plants which require to live ina 
pure and often renewed air, have a straight stem, either robust or 
slender, according to their individual habit. Where they require 
a moist and denser atmosphere, when they have to creep along the 
ground or to glide among the brambles, the stems are usually 
: long, flexible, and trailing. If 
they have to float in the air, sup- 
porting themselves on plants of 
more robust growth, or to hang 
suspended from forest trees in 
graceful festoons and light gar- 
lands, they are provided with 
flexible, slender, and pliant stems, 
which enable them to embrace 
with their tendrils the trunks of 
trees or shrubs. Thus, nature 
fashions the outward forms of 
plants according to the part which 
cording to the functions which 
have been allotted to them. 
Nothing is more variable than 
the appearance of the stem in vege- 
\\ tables and trees; in their infinite 
*&\ variety they sometimes present 
’ to us perfect types of beauty 
and elegance. Sculpture and 
painting have borrowed from the 
trunks of certain trees, models of 
Fig, 22,—Bindweed. architecture at once elegant and 
majestic; types which have been 
handed down to us from the most remote antiquity, and which are 
still the models in use. Man has discovered in vegetable forms his 
first designs for adornment, construction, and . The stem 
of the Palm-tree and the Date-tree, and the leaves of the Acanthus, 
formed a model for the majestic columns of the Corinthian order ; 
the leaves of the vine and the natural garlands of young climbing 
they are intended to fill, and ac- _ 
