SECTION IX. GYMNOSPERMS 



A. CYC AD ALES (CYC ADS) 

 SPOROPHYTE 



1. Habitat and relationships. 



a. Consult the text and assigned readings concerning 



the habitat, classification, and relationships of the 

 Cycadales. What is the natural habitat of the 

 cycads in the United States ? Were they ever more 

 abundant and important as a part of the world's 

 vegetation than they are at the present time ? What 

 position in classification do they occupy among 

 living plants ? What ancestral relationships have 

 they which make them important to study in a 

 course in plant evolution ? 



b. Summarize answers to the above questions in your 



notes. 



2. Habit and body plan. 



a. What is the body plan of cycads ? See the arrange- 



ment of leaf bases and green leaves on the stem. 

 Do you know of ferns or seed plants which the 

 cycads resemble in general habit? Are the cycads 

 closely related to such plants ? 



b. Leaves. Study young and mature leaves of cycads. 



In what respects do cycad leaves resemble those of 

 ferns ? If leaves are unfolding, notice the method 

 of unfolding of the entire leaf and of the pinnules. 

 If possible, note the venation of leaves of Cycas and 

 Zamia, Are the resemblances of cycad leaves to 

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