A. 
STUDY 3. 
STEMS AND THEIR MODIFICATIONS. 
(a) (Desirable material for typical stems are corn and 
10. 
11. 
asparagus, smilax, and other woody stems which 
will show various bud arrangements.) 
Find one or more scars at each node of various speci- 
mens. What causes them ? 
How are the scars related to each other ? 
What is the position of the buds with reference to 
the scars ? 
How do the internodes compare in length on the 
same and different stems ? 
In woody stems observe zones of scars at irregular 
intervals. What is their origin? What do they 
signify as to linear growth? 
Compare these intervals on the same stem and on 
stems of different plants. What conclusions do you 
draw from this comparison ? 
The small speck-like structures on the internodal 
surface are breathing pores called lenticels. What 
is their form and relative number ? 
What is their form on stems of different years’ 
growth? Why? 
Are the lenticels closed or open? 
In what respect do apical and lateral buds differ? 
How and why are winter buds protected? Into 
what will they develop? 
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