108 THE WORK OF PLANTS 
seen. A section of the stem of a palm shows that here, 
also, the vascular bundles are arranged irregularly. 
Plants with netted-veied leaves usually have the 
vascular bundles arranged regularly m rings, while 
plants with parallel-veined leaves usually have the 
vascular bundles arranged irregu- 
larly. Compare the arrangement 
of the veins on the leaves of the 
garden balsam, coleus, begonia, 
bean,. pea, sunflower, oak, etc., 
with the arrangement of the 
vascular bundles. The leaves are 

netted-veined, and the bundles are 
Fic. 144. Cross section of palm . : ] : : C ‘ ij 
stem, There are no annual IN regular rings. Compare the 
a veins in a lily leaf or in a blade 
of maize, wheat, oat, or grass with the arrangement of 
the bundles. The leaves are parallel-veined, and the 
bundles are arranged irregularly. You will remember 
that the bean, pea, oak, etc., have two cotyledons in the 
seedling, and that the maize has only one. 
What kind of venation in the leaves, and what 
arrangement of the vascular bundles are usually found 
in plants with two cotyledons? In plants with a single 
cotyledon? What are these two large groups of plants 
called ? 
