26 OBSERVATIONS ON FOSSIL VEGETABLES, 
Fig. 10. Sandal, or Sanders Wood. ‘Transverse section. ‘This wood 
approaches in its characters to the above, but is more compact in its texture, 
and has the layers united, without any appearance of the lines of junction 
so apparent in the others. 
These portions of sections will be understood by referring to Fig. 15, 
which represents part of a transverse section of a twig of the Common Ash, 
Frraxinus excelsior. Tere there are seen,—a central column of cellular 
texture, the pith ; concentric layers of woody texture, shewing divergent 
medullary rays, elongated cellular tissue, and large openings of vessels ; 
and, lastly, the bark. In short, the general structure and mode of growth 
are the same as in the Conifer; but a transverse section of the trees of 
this class, the Dicotyledonous Phanerogamic, is easily distinguished from 
that of trees of the former class. The large openings of the vessels, in par- 
ticular, symmetrically arranged, between the more or less flexuose medullary 
rays, and the denser texture of the cellular part, are characteristic. 
Fig. 11. Sugar Cane, Saccharum officinarum. ‘Transverse section of 
a portion of the stem, shewing opaque spots of an oval form, and perforated 
by vessels, contained in a uniform mass of cellular tissue or parenchyma. 
Fig. 12. Transverse section of part of the stem of a species of Calamus, 
exhibiting a similar arrangement. 
The appearances here will be understood by referring to Fig. 13, which 
represents a portion of a transverse section of the stipe of Rhapis flabelli- 
JSormis, from the centre to the surface. Here the structure is very different 
from that of the other two classes. These plants belong to the class of the 
Monocotyledonous Phanerogamic, which, in the transverse section of their 
stems, exhibit vascular bundles imbedded in cellular texture, without con- 
centric layers or regular bark. 
In conclusion, 
Fig. 13. represents the Monocotyledonous stem, shewing the vessels 
imbedded in cellular tissue, which is looser at the centre, more condensed 
toward the surface, but not arranged in regular series, bounded by medul- 
lary rays, as in the Conifer and Dicotyledones. There are no medullary 
rays, nor any appearance of concentric layers. 
