THE FLORIST AND POMOLOGIST. 
20 
[January, 
We commence with Professor Bentley’s Manual of Botany,* of which 
a new edition has recently been issued. The work, as is well known, is one of 
those general compendiuins intended to be used as a class-book by students. It 
is divided into three books, the first of which (pp. 6-385) is devoted to Organo¬ 
graphy, or Structural and Morphological Botany ; the second (pp. 386-727) to 
Systematic Botany, or the Classification of Plants; and the third (pp. 728-808) 
to the Physiology of Plants. The text is illustrated by upwards of 1,100 small 
but characteristic figures, a sample of which, by the courtesy of -the publisher, 
we here introduce. This second edition has been thoroughly revised, so as to 
adapt it to the present state of botanical science, and especially as regards the 
two first books will be found full and particular ; the physiological branch of 
the subject being much more briefly treated. We select one or two passages for 
abstract, which may be useful to our younger readers ; and first a few remarks 
relating to the Root:— 
“ The true root, which can only exist in dicotyledonous plants, is formed at first by additions 
made within the extremity of the radicle, and the mode in which it takes place may be thus 
stated:—Growth commences by the multiplication of cells, by divisions just within the apex of 
the radicle ; these cells then elongate by their own inherent vitality, by which the tissue con¬ 
stituting the apex is pushed onwards, and gradually perishes, or is thrown off; the innermost 
of these newly-formed cells then remain unaltered, while others immediately within the point 
of the root continue to multiply by division, and grow in a similar manner to the former, by 
which the layer of tissue at the apex is again pushed forward, and pei'ishes in like manner as 
before. Roots do not grow, therefore, throughout their entire length like stems, but only 
within their extremities, which are continually pushed forward and renewed. Thus the apex of 
the root is always clothed by a layer of denser tissue than that which is within it. This layer 
is termed by some botanists the pileorldza. It forms a sort of protecting shield to the young 
extremity of the root. The extremities of the root were formerly regarded as special organs, 
and called spongioles or spongelets (fig. 1, sp), under the idea that they absorbed fluid for the 
use of the plants in the same manner as a sponge 
sucks up water. But it will be seen from the above 
description of the growth of roots that such struc¬ 
tures have no existence. Roots increase in diameter 
by the formation of annual layers of wood, in the 
same manner as stems.” 
“ At first the elongatiug, growing extremities of 
roots consist entirely of parenchymatous cells (fig. 
1, c) ; wood-cells and vessels (fig. 1 ,fv), however, 
soon make their appearance, and are constantly 
added to below by the new tissue formed as the 
root continues to lengthen.Externally there 
is a true bark, which is also covered when young 
by a modified epidermis without stomata, sometimes 
called epibfoma. This epiblema is also furnished 
with hair-like prolongations, w T kick are commonly 
termed fibrils or fibridce (fig. 2). These fibrils are 
Fig. 1. Vertical Section Fig. 2. Fibrils on Surface especially evident upon young growing roots, and as 
of Root. of Young Root. these advance in age they perish, while the tissue 
from which they were prolonged becomes at the same time harder and firmer.” (p. 114.) 
In a subsequent page (744), the function of the root is explained. It is that 
of absorbing nutriment for the uses of the plant, a function almost wholly 
confined to the cells and fibrils (fig. 2) of the younger portions. Hence trans- 
* A Manual of Botany: including the Structure, Functions, Classification, Properties, and Uses of Plants. By 
Robert Bentley, F.L.S., Professor of Botany in King's College, &c. London: J. Churchill and Sons. 
