XU 
INTRODUCTION. 
8. Woody Tissue, which makes up a large part of trees and shrubs, but 
also exists in herbs, consists of cells with firm and thickish walls, drawn 
out into tapering or slender tubes. Their diameter is usually much less 
than that of ordinary cells : from their tenuity and form, as well as from 
the appearance of the threads, which by their combination in bundles they 
often produce, they are likewise called Woody Fibre. 
9. Vessels are elongated cells of various kinds, usually of larger size 
than woody fibre, or tubes formed by the confluence of a row of cells, gen¬ 
erally accompanied or surrounded by woody tissue. Their walls are com¬ 
monly marked with lines, bands, or dots, or, in the Spiral Vessel, 
strengthened by a coil of a delicate fibre adherent to the inside. The 
larger vessels, such as those which form the pores so apparent to the naked 
eye on the cross section of many kinds oftwood, are termed Ducts. This 
name is also applied to most kinds of vessels in which the spiral fibre, if any, 
is incapable of being uncoiled by extension. 
10. The cells and vessels are the organic elements, the tissues or 
fabric of plants. They are fashioned into the organs, or visible parts of 
the vegetable. 
11. The organs of plants are of two sorts : — 1. those of Vegetation, which 
are concerned in growth, — by which the plant takes in the aerial and 
earthy matters on which it lives, and elaborates them into the materials of 
its own organized substance ; 2. those of Fnictification or Reproduction, 
which are concerned in the propagation of the species. 
3. Organs of Vegetation in General. 
12. The organs of vegetation are the Root , Stem, and Leaves. 
13. The Stem is the axis and original basis of the plant. It is made up 
of a succession of naked joints (internodes), separated by leaf-bearing 
points (nodes), developed each from the apex of the preceding one. 
14. The growing apex, generally furnished with rudimentary leaves, to 
be developed as it develops by the elongation of ihe internodes succes¬ 
sively, is a Bud. # 
15. The first point of the stem preexists in the embryo (i. e. in the ru¬ 
dimentary plantlet contained within the seed): it is here called the Rad¬ 
icle. Its elongation when the seed germinates in the soil commonly 
brings the budding apex to or above the surface, where the leaves which it 
bears or produces expand in the light and air. The growth which takes 
place from the opposite extremity downward, penetrating the soil and 
avoiding the light, forms the Root. 
16. The plant, therefore, has a kind of polarity, and develops from the 
first in two opposite directions, viz. upwards to produce and continue the 
stem (or ascending axis), and downwards to form the root (or descending 
axis). The former is ordinarily or in great part aerial, the latter subter¬ 
ranean. 
17. Accordingly, the essential organs of the plant, by an inherent and 
irreversible tendency, are developed in the media in which they are sev¬ 
erally designed to live and act*, —the root in the soil, from the moisture of 
which it imbibes nourishment; the stem with its leaves in the air, upon 
which these operate in vegetable digestion, and exposed to the light of the 
sun, whose influence is directly essential to this operation. 
3. The Root. 
18. The Root branches indifferently from any part; but its branches and 
branchlets (rootlets) are mere repetitions for the purpose of multiplying 
the absorbing points, which are chiefly the growing or newly formed extrem¬ 
ities, sometimes termed spongelets. It bears no other organs. 
