> : STEMS. Es i 
Dicotyledonous Stems. 
The stem is that portion of a plant which connects 
the roots with the leaves. It bears leaves and conse- 
quently must contain buds. 
Thoroly inspect a horse-chestnut twig about 40 cm. 
long. The twig has several buds and is consequently 
a portion of astem. What is the general character of the 
bark? How does it differ in different parts of the twig? 
Note the horse-shoe shaped scars, leaf-scars, What are 
they caused by? Are they alternate or opposite? Note 
the dots on the leaf-scars? Does the number vary in 
different scars? The instructor will explain, to the class 
as a whole, what has caused them. That portion of the 
stem directly underneath a leaf-scar is called a nede; the 
portion between two consecutive scars an internode. 
Are the internodes of different twigs and portions of the 
same twig grown in different years the same in length? 
Rings composed of small narrow scars, scale-leaf- 
scars, will be found on the twigs. Remove the scale 
leaves which surround a terminal bud one by one. How 
are they arranged, alternate or opposite? How many 
are there? What do you find in the bud? What plant 
structures develop from buds? Can you now ascertain 
what causes the rings above mentioned? How many 
terminal buds develop in a twig in a year? How old 
is the twig studied, at its larger end? How many centi- 
