SOME LESSONS IN BOTANY 61 
Type 7. Burrowing or underground stems have some 
resemblance to roots and are easily mistaken for them. The 
plant commonly uses these stems 
for the storage of food, and 
therefore they have capacity for 
vigorous growth. A small sec- 
tion of an ordinary underground 
stem or rootstock, if severed 
from the rest of the plant, will j 
at once proceed to do business UnpERcrounp Srem or Roor- 
as a complete and independent oe 
plant. Some of our worst weeds, as quack grass and Canada 
thistle, owe their persistence to their underground stems. 
Type 8. The Irish potato is an abnormal enlargement of 
the end of an underground stem. Such a growth is called a 
tuber. The “ eyes”’ of the potato are the buds. 
THE FLOWER 
The Purpose of Flowers. — 
Flowers are the favorite objects 
in all nature. We prize them 
for their fragrance and delicate 
beauty, and we grow millions 
of plants in this country solely 
for the sake of their blossoms. 
When we cannot have the flow- 
ers themselves to please our sense 
of smell, we often make use of perfumes containing their pre- 
cious essence. We are, therefore, apt to think that flowers 
grow for our special benefit, and this may in a sense be true 
of some cultivated varieties, like double roses and asters, that 
man’s ingenuity has greatly changed by developing the size, 
Potato AS AN UNDERGROUND STEM 
