214 PHARMACEUTICAL BOTANY 
Microscopic CHARACTERISTICS OF ANGIOSPERMOUS AND 
Conrrerous Woops.—The wood of Angiosperms is character- 
ized by the presence of tracheze (vessels) with various markings 
on their walls, particularly by small pits in the walls of some of 
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B 
Fic. 143.—A, diagram of the course of vascular bundles in a palm stem (mono- 
cotyledon); 1m, 2m, 3m, bundles from the median portions of the leaves. B, 
diagram of vascular bundles in external view and in cross section of the dicotyledon- 
ous stem of Cerastium. The leaves are shown cut off at 1, 2, 2’ and 3. (After 
Vines.) 
the tracheze, together with wood fibers, fiber tracheids,' wood 
parenchyma cells and medullary-rays. 
The wood of Conifers is made up for the larger part of 
tracheids with bordered pits which latter are characterized in 
radial longitudinal section by the presence of two rings, one 
within the other. A single row of these is seen on the tracheid 
wall. Medullary-rays, frequently diagnostic for different species, 
and wood parenchyma cells (in larches and Douglas Fir, etc.), 
are also found. 
1 Forms intermediate between typical tracheids and wood fibers. 
EE eS eS Pe. Se 
