34 LABORATORY PRACTICE CHAP, vi 



III. Examine a flowering branch of one of the true 

 Honeysuckles and notice that : 



1. The lower leaves are in pairs and entirely separate. 



2. The leaves toward the end of the branch are also in 



pairs and are sometimes united around the stem by 

 the growing together of their bases. 



3. The uppermost pair are grown completely together. 



4. Such leaves as these uppermost ones are said to be con- 



nate-perfoliate. 



5. Make a sketch of the branch and the various pairs of 



leaves to show these characters. 



IV. Examine an Acacia leaf (not an Acacia with the 

 compound leaves, but one with what appear to be simple 

 leaves) and notice : 



1. The general shape. 



2. The venation. 



3. The position upon the stem. It is attached to the stem 



in such a way that its edges point up and down, i.e. 

 it is vertical in position. 



4. This vertical attachment shows that it is really a peti- 



ole (without any blade at all) very much flattened, 

 serving the purpose of a blade. Such structures are 

 called phyllodia. (An additional proof that these 

 phyllodia are flattened petioles is afforded by the 

 fact that seedlings of the phyllodia-bearing Acacias 

 usually have the first few phyllodia bearing regular 

 compound blades at their tips.) 



5. Make a sketch to show the phyllodia. 



V. We have studied leaves without stipules, leaves with- 

 out either petioles or stipules, and leaves consisting only 



