92 ~~~ Structural and Physiological Bota 
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_ bearing leaves, while the latter does not. ‘Leaves are 
lateral [or appendicular] organs which do not possess any 
- capacity of development of their own, and which may there- 
fore be regarded in many respects as appendages attached 
to the entire organism, not possessing an independent life. 
~ It follows therefore naturally that the leaves and axis are 
subject to different laws of growth :—the axis grows at its 
_ apex, and the leaves at their base where they are attached to 
the axis. New leaves are developed only at the extreme end 
of the branch.. The roots, on the other hand, have no 
power of forming leaves, because the outermost cells of their. 
‘nuncta vegetationis’ die very early, and then cover it in 
the form of a cap (Fig. 100, w%). Beneath this rvot-cap, 
as it 1s termed, the production of new cells continues ; 
while the cap itself acts as a protecting shield to the root 
when it penetrates into the hard soil. ‘The growth in length 
of roots ceases therefore so near their apex that the portion 
which is at any time actually increasing in length is usually 
- only a few millimetres long. 
In the remainder of this chapter no reference will be made to 
flowerless plants, but only to flowering plants or Phanerogams, since the 
morphology of the former is so closely connected with their classification 
that it will be better spoken of under that head. Much, however, that 
is now described applies equally to both classes [at least to those 
Cryptogams which are’also cormophytes], especially all that relates to 
the branching of the axis, the buds, phyllotaxis, the forms of leaves, 
secondary organs, &c. 
THE ROOT. 
The Root is that part of the plant which, usually growing 
- downwards, fixes it into the ground, and absorbs nutri- — 
ment out of the soil. It bears at its apex a root-cap, and 
~ never developes leaves. | 3 
Some plants have certain characteristic kinds of roots which do not ‘ 
in all respects answer the description given above. Thusc/asping roots, ~ 
_as those of the ivy, often penetrate laterally into trees, rocks, or walls. _ 
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