2 
LABORATORY EXERCISES 
2. Find the lateral roots, which arise from the base of the plant 
and, after descending a short way, extend out almost horizontally 
for twenty inches or more. 
3. Next note the brace roots, which appear from the nodes of 
the stalk just above the ground. What is the use of the brace 
roots? What is the time of their appearance? 
II. Stem. What is the form of the stem? Note the nodes and 
internodes. What is the nature of the surface of the stem? Study 
a cross section. How does the outer part differ from the inner? 
How does this arrangement affect the rigidity of the stalk? Ob¬ 
serve the numerous small fibers in the inner part or pith of the stem. 
These fibers are the fibrovascular bundles. 
III. Leaves. Note the arrangement, the size, and the number 
of the leaves. Where are the leaves attached to the stem? The 
lower part of the leaf is the sheath; the free upper part is the blade. 
Note the scale-like appendage at the division of the sheath and 
the blade. Note the midrib of the blade. How are the veins 
arranged with relation to the midrib? 
IV. Flowers. (See Waggoner, Fig. 4.) 
1. The Tassel. Where is the tassel? What are the chaffy 
structures on its branches? What do these produce? 
2. The Immature Ear. Remove the husks. Note their ar¬ 
rangement and structure. The corn kernels are formed from the 
flowers which are borne on the cob. What is the relation of the 
silks ” to the kernels? 
V. Make a drawing of a complete stalk of corn. 
(Note — Begin preparations for the growth of corn and bean 
seedlings in order to allow at least 15 days for this before the seed¬ 
lings are to be used. See Exercise 11.) 
