130 A TEXTBOOK OF GENERAL BOTANY 
the structure and arrangement of the bundles that monocotyle- 
donous stems differ markedly from dicotyledonous stems. : 
Stele. “The vascular bundles of monocotyledonous stems, 
instead of being arranged in a cylinder as in dicotyledonous 

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Ita. 125. Cross section of a monocotyledonous stem, Saccharum spontaneum 
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The dark oval areas are cross sections of vascular bundles. (x 25) 
stems, are usually scattered throughout the stele, including the 
pith, so that there is no distinction between pith and pith rays : 
(Higs. 125, 126). Sometimes the center of the stele is free 
from vascular bundles and_ is occupied by parenchyma cells, : 
which dry up and disappear at an early stage, resulting in a 
hollow stem, as in most grasses, including most bamboos. 
Plea 
