ARRAyGJSMENT OF THJS BUDS 63 



leaves; 10, involute opposite leaves; 11, involute alternate leaves; 

 12, revolute opposite leaves; 13, equitant two-edged; 14, equitant 

 three-sided. In writing of flowers, it is the custom of systematic 

 botanists to describe them as valvate when the edges of the parts 

 simply meet in the bud, and to call them imbricate when they dis- 

 tinctly overlap. 



Suggestions. — The pupil should now examine the bursting buds 

 of the plants which he meets. He will be interested to discover 

 the almost infinite variation in method of vernation, and he will 

 see that this method does not always fall readily into the various 

 categories which have been named and described. There are all 

 kinds of intermediate methods. For an ill-defined, crumpled-plicate 

 vernation, examine the rhubarb. To show the small modifications 

 in the same general method, examine the leaves (when just appear- 

 ing) of the lilac and the peach, and observe the position of the 

 leaf- edges. The general conclusion will be that some one method 

 is fairly constant in each kind of plant, and is, therefore, character- 

 istic of the plant. 



XII. ARRANGEMENT OF THE BUDS 



64. The honeysuckle shoot (Fig. 56) shows at 

 a glance that the leaves are arranged in a defi- 

 nite order ; and if there is an arrangement of 

 leaves, there is also an arrangement of buds. In 

 this case, the leaves are in pairs, one leaf ex- 

 actly opposite the other upon the stem. More- 

 over, the pairs alternate in arrangement. That is, 

 if one pair, a a, stands east and west, the suc- 

 ceeding pair, h b, stands north and south, and the 

 third pair, c c, stands east and west agaiu. The 

 third pair is, therefore, perpendicularly over the 



