84 FOUNDATIONS OF BOTANY 
bundle of a leaf. This fact being known to the student would lead 
him to expect to find the bundles bending out of a vertical position 
more at the nodes than elsewhere. Can this be seen in the stem 
examined ? 
Observe the enlargement and thickening at the nodes, and split 
one of these lengthwise to show the tissue within it. 
Compare with the corn-stem a piece of palmetto and a piece of 
cat-brier (Smilax rotundifolia, S. hispida, etc.), and notice the simi- 
larity of structure, except for the fact that the tissue in the palmetto 
and the cat-brier which answers to the pith of the corn-stem is much 
darker colored and harder than corn-stem pith. Compare also a piece 
of rattan and of bamboo. 
97. Minute Structure. — Cut a thin cross-section of the corn-stem, 
examine with a low power of the microscope, and note: 
(a) The rind (not true bark), composed largely of hard, thick- 
walled dead cells, known as sclerenchyma fibers. 
(b) The fibro-vascular bundles. Where are they most abundant ? 
least abundant ? 
(c) The pith, occupying the intervals between the fibro-vascular 
bundles. 
Study the bundles in various portions of the section and notice 
particularly whether some are more porous than others, Explain. 
Sketch some of the outer and some of the 
inner ones. 
A more complicated kind of monocoty- 
ledonous stem-structure can be studied to 
advantage in the surgeons’ splints cut from 
yucca-stems and sold by dealers in surgical 
supplies. 
98. Mechanical Function of the 
Fig. 53. — Diagrammatic 
Cross-Section of Stemof Manner of Distribution of Material 
Bulrush (Scirpus), a 
Hollow Cylinder with in Monocotyledonous Stems. — The 
Strengthening Fibers. 
well-known strength and lightness of 
the straw of our smaller grains and of rods of cane or 
bamboo are due to their form. It can readily be shown 
