FORMS OF THE PETIOLE. 



33 



F!g. 80. Amplexioaul leaves of Aster laevis. 



Fig. 81. Perfoliate leaves of Bell wort (CTowto-iayej/oKaia). 



Fig. 82. Connate leaves of Honeysuckle {Lonicera sempenirens). 



43. In Fig. 82 (Trumpet Honeysuckle) the leaves placed 

 opposite are joined together hj pairs, base to base. Such 

 are connate leaves. 



44. The forms of the petiole, when the petiole exists, are 

 Mso various. Generally, it is merely a rounded, slender 

 stem, but you will often find it flattened. Have you ever 

 noticed the structure of the Aspen (Poplar) leaf, which so 

 easily flutters in the gentlest breeze ? Its petiole is flattened 

 vertically, so that its edges turn sky-ward and earth-ward. 

 Such a form of leaf-stalk is called oompressedf, and it must be 

 very nicely balanced in order to hold the blade at rest. 



43. When are leaves said to be connate ? 



44. What is the usual form of the petiole? 



of the Aspen. 



3* 



Carefully descrihe the petiole 



