Download PDF

EXPLANATION OF THE PLATES.
PLATE THE FIRST.
ANATOMY OF THE STEM.
Fig. 1. Platanus orientalis, SalicincE. A transverse
section of a young branch, to exhibit the organization,
-which is similar to that of the grei^ter part of dicotyledon
trees.
Fig. 2. A magnified representation of a portion cut out
of the above section.
a to b. Bark.
'
a to c. Outer part of the bark, dry and disorganized.
I to c.
c to d.
The live part of the bark.
A part of the bark which is continually pushed
to the circumference.
Ij to d. Inner part of the bark, called the liber or bast.
e. The origin of the medullary radii that fill up the in-
terstices of the wood, and which are formed of the cellular
tissue of the bark.
The extremity of the filaments that form the inter-
J'.
stices of the wood.
b to i. The woody mass, composed of three zones, or
layers, b— g, g — h, and h—i.
h to i. The oldest of the three layers.
gto h. The second layer.
b to g. The third or youngest layer.
b, g, and h. Zones which show the periods when the vegetation
slackened.
i to k. Pith.
Fig. 3. Ptychosperma gracilis. Palmes. Vertical and
transverse section of the stem, to show the diiference between
the stems of monocotyledon plants and those of dicotyledon
plants.
Fis- '^- A mao;nified figure of the same.
a to b. That part of the stem where the hardest woodj
iibres are the most closely collected together.