Chap. 56.] 
THE EOOTS OI' TREES. 
393 
thickness througlioiit. Some trees divide into branches from 
the very ground, as in the apple-tree, for example. 
• CHAP. 55. (31.) THE BAEK OF TEEES. 
In some trees the bark^° is thin, as in the laurel and the 
lime ; in others, again, it is thick, as in the robur ; in some it is 
smooth, as in the apple and the fig, while in the robur and the 
palm it is rough : in all kinds it becomes more wrinkled when 
the tree is old. In some trees the bark bursts spontaneously, 
as in the vine for instance, while in others it falls ofi' even, as 
we see in the apple and the arbutus. In the cork-tree and 
the poplar, the bark is substantial and fleshy ; in the vine and 
the reed it is membraneous. In the cherry it is similar to 
the coats of the papyrus, while in the vine, the lime, and the 
fir, it is composed of numerous layers. In others, again, it is 
single, the fig and the reed for instance, 
CHAP. 56. — THE EOOTS OF TEEES. 
There are great differences, too, in the roots of trees. In the 
fig, the robur, and the plane, they are numerous ; in the apple 
they are short and thin, while in the fir and the larch they 
are single ; and by this single root is the tree supported, al- 
though we find some small fibres thrown out from it laterally. 
They are thick and unequal in the laurel and the olive, in 
which last they are branchy also ; while in the robur they 
are solid and fleshy .^^ The robur, too, throws its roots down- 
wards to a very considerable depth. Indeed, if we are to be- 
lieve Virgil,^'-^ the sesculus has a root that descends as deep 
into the earth as the height to which the trunk ascends in the 
air. The roots of the olive, the apple, and the cypress, creep 
almost upon the very surface : in some trees they run straight 
and horizontally, as in the laurel and the olive ; while in others 
they have a sinuous course — the fig for example. In some 
trees the roots are bristling with small filaments, as in the 
fir, and many of the forest trees ; the mountaineers cut off 
^ It is evident that he is speaking of the epidermis only, and not the 
cortical layers and the liber. 
6^ The roots of trees being ligneous, " carnosae," Fee remarks, is an in- 
appropriate term. 
6- Georg, ii. 291. 
