112 BOTANY. 
ground, sending down roots into the soil, and sending up shoots into the 
air, is called a root-stock, Examples may be seen in the yellow iris and 
in Solomon’s seal. Whilst some plants have strong and erect stems, 
capable of sustaining all the weight of their branches and leaves, the stems 
of others are slender and weak, trailing along the ground, or depending 
upon other plants for their support. Of those which seek the support of 
other plants, some are provided with tendrils, by which they lay hold of © 
them, and others twine around them. The pea is an instance of a 
climbing plant, and its tendrils coil in an admirable manner around the 
branches to which it clings. The scarlet runner is a twining plant: it 
has no tendrils, but its long stem twines round any pole or branch with 
which it meets. It is remarkable that twining stems always twine ina 
particular direction, some from right to left, others from left to right. 
The scarlet runner twines from right to left, the hop and the honey- 
suckle twine from left to right. Climbing and twining plants greatly 
abound in tropical countries, and contribute much to the prodigious 
density of vegetation in the forests, some of them ascending to the tops 
of the most lofty trees, and falling down again from their high branches, 
rich in foliage, and often also in flowers of the greatest beauty, or binding 
tree to tree, so that the forest becomes impenetrable. 
Soft stems are called herbaceous, and the plants to which they belong 
are called herbaceous plants, in contradistinction to trees and shrubs, which 
are woody plants. Herbaceous stems are often annual—that is, their 
existence is limited to a single year. They rise from the ground in spring, 
and die on the approach of winter, even although the root may survive. 
Woody stems subsist during the whole life of the plant. 
Buds and Branches.—Stems, as they grow, produce buds. The stem 
always terminates in a bud; and in some plants, as in the greater number 
of palms, this is the only bud. In this case, there are no branches, what 
are often spoken of as the branches of palms being really leaves of extra- 
ordinary magnitude. Branches proceed from lateral buds. The buds of 
some plants arise only from certain well-marked points of the stem, called 
nodes} or knots, which appear as joints, of which a strongly marked example 
is found in the bamboo ; and although this cannot be so clearly observed 
in other plants, yet in all a certain rule is followed, so that the buds 
do not appear irregularly scattered, but arranged according to a definite 
method. Thus the arrangement, of leaves is different in different 
plants; in one they are in pairs on opposite sides of the stem, in 
another they spring from opposite sides alternately, while in some 
they are found in whorls. They are very generally arranged in a kind of 
spiral manner around the stem. A similar diversity of arrangement 
1 Greek nodos, a knot, 
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