1 94 MORPHOLOGY AND LIFE HISTORY 



3. The Aerial Branch. 



(a) Describe its general appearance, shape, length 

 (compare several different specimens), color- 

 ation (color-pattern), and presence or absence 

 of branches. 



(>) At which end of the rhizome is it borne? Is 

 it a terminal or a lateral outgrowth? Is it an 

 axillary organ (i.e., borne in the axil of a leaf), 

 or not? On a node or an internode? 



(c) Make a drawing 20 mm. in diameter, showing 

 the distribution of the fibre-vascular bundles 

 as seen in cross-section. 



(d) What does the branch bear at its summit? 

 Do you find any exceptions to this? 



D. The Roots: 



1. Describe their distribution on the root-stalk. Do 

 they occur on both nodes and internodes? State 

 the significance of the observed distribution. 



2. Record the presence or absence of branching. 



3. Compare the appearance of new roots with that 

 of older ones. On what part of the rhizome are 

 they borne? 



4. Describe the surface appearance of older roots. 

 Remove a root 3 to 4 cm. long, hold it by each end? 

 and gently pull (not hard enough to break the 

 root). How does this affect the surface appear- 

 ance? How do you think the original feature 

 was produced? 



5. With the scalpel cut a root squarely off near its 

 base and observe the cross-sectional view. Dis- 

 tinguish three tissue-systems: (a) the epidermis; 



(b) the central cylinder; (c) between (a) and (b), 

 the cortex. 



