26 
LABORATORY EXERCISES 
EXERCISE 28 
VEGETATIVE PROPAGATION OF PLANTS 
The members of the class may bring specimens to be used in this 
exercise. Cuttings of some house plant such as a geranium should 
have been placed in water about two weeks previously. 
I. The Runner. Note one of the slender branches which is sent 
out from the main plant of the strawberry or common cinquefoil 
(the five finger Observe the position of the tip of such a 
runner. Does the runner have nodes? Does it have leaves? 
What is likely to occur where such a runner touches the ground? 
The runner is called a stolon. Name other plants which may be 
propagated by some similar method. 
II. The Underground Stem. 
1. Study the “ quack grass ” (couch, quitch, or quick grass — 
Agropyron repens). Dig up an entire plant. Where are the roots? 
Examine the underground stem. How does it differ from the roots? 
Note its branching and find nodes if nodes are present. What is 
the function of this underground stem? Why is the plant hard to 
kill out? Such an underground stem is called a rootstock or rhizome. 
2. Examine the tuber of an Irish potato. What is its shape? 
Its markings? Its covering? Where was it attached to the parent 
plant? Where are the “ eyes ” most numerous? What are the 
“ eyes ”? What is the arrangement of the eyes ”? What por¬ 
tion of the plant is represented in the tuber of the Irish potato? 
What is the function of the tuber? Of what use to the plant is the 
food which is stored in the tuber? What part of a potato do we 
plant in order to grow other potatoes? Why can we divide a tuber 
and grow several hills ” from it? Why is the seed of potatoes 
almost never used? Draw a tuber. 
III. Cuttings of geraniums or other house plants which have 
been “ rooted ” may be examined. Note the position of the roots 
on the stem. Draw. 
IV. In the propagation of plants, what are the advantages of 
the use of vegetative means as compared with the use of seeds? 
