SECTION III. ANATOMY 



A. ANATOMY OF STEMS 

 EXTERNAL FEATURES OF WOODY STEMS 



Review the following important external features of shoots 

 of some common tree like the ash or hickory. See your pre- 

 vious work on the shoot and buds of lilac and elm. 



1. Buds and their relation to growth. 



a. How many kinds of buds, as regards position, are there 



on the shoot you are studying ? Which buds are 

 definitely related to nodes ? Are the different kinds 

 of buds of the same size ? How many buds of pre- 

 vious years grew into the main shoot or into lateral 

 branches ? Are the other buds still alive ? Would 

 they ever have grown into branches ? 



b. Age of shoots. Can you determine how many years of 



growth are represented in the shoot you are study- 

 ing ? How are the yearly segments of growth marked 

 off ? What is the cause of these markings ? 



2. The bark and its markings. Is the bark uniform in color 



and appearance in the older and younger portions of 

 the shoot, representing different years of growth ? Peel 

 off or scrape off the outermost thin brown skin with a 

 scalpel; what is the color of the tissue beneath it? 

 Now scrape down to the wood ; do you find any new 

 tissue layers comprising the bark of the twig ? 



3. Scars and markings on the bark. 



a. What large scars and markings do you find on the bark 

 of the entire twig ? What is the nature and position 



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