108 ELEMENTS OF PLANT ANATOMY. 
of vascular tissue, the main features of its method of growth 
are as follows. 
Leaf-trace bundles occur in every stem, and in many there 
are also stem bundles. When the latter occur they run near 
the periphery and nearly parallel with the long axis. The 
peculiar course taken by the leaf-traces in the stem is the 
De 
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( 
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Diagrammatic representation of the course of the vascular bundles in a monocotyledonous 
stem. A radial long section. #B cross-section. C horizontal projection of the leaf- 
traces. m medial, m’ marginal nerve. — ( Wiesner.) 
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WH) 
FIG. 46. 
cause of the scattered arrangement of bundles on the cross- 
section. There are usually a large number of bundles from 
each leaf which enter the stem separately, and take a radially 
oblique course; in some large plants the number reaches 
several hundred. The leaf basis extends entirely around the 
stem circumference, and from this basis each bundle continuing 
downward enters the stem bending strongly toward the centre, 
