THE PALM TREE. 125 
which it assumes, while they all partake of the same 
general outline and character. 
It will be remember- 
ed that in speaking of 
the growth of trees, we 
mentioned that the fresh 
deposits of wood are 
made on the external 
surface of the trunk, im- : 
mediately under the ee NR ag 
bark. This is the case NS 
with all the trees, with a Endogenous Wood. 
few exceptions, found in the Temperate Zone, and 
they belong to the Exogenous plants. But the Palm 
may be regarded as the type of the third natural order, 
called Endogenous, which has been heretofore de- 
scribed; and by reference to the adjoining cut, the 
peculiar arrangement of the particles of the wood 
may be contrasted with that of the exogenous tree. 
In the exogenous, the centre or heart-wood is the 
hardest; the new growth is more spongy, while the 
bark is quite soft. In the endogenous, the exterior 
is hard and tough, and the interior is soft, and often 
pithy. 
The Palms are lofty and erect trees, with slender, 
cylindrical stems, simple or rarely forked, and are 
marked more or less distinctly with knots or rings, 
which show the position of leaves which have de- 
cayed and fallen, and also indicate the progress of 
their growth. The leaves, which are large, often 
11* 
