FORMS OF THE PETIOLE. 338 
Fig. 80. Amplexicaul leaves of Aster laevis. 
Fig. 81. Perfoliate leaves of Bellwort ( Voularia perfoliata). 
Fig. 82. Connate leaves of Honeysuckle (Lonicera sempervirens). 
43. In Fig. 82 ([rumpet Honeysuckle) the leaves placed 
opposite are joined together by pairs, base to base. Such 
are connate leaves. 
44, The forms of the petiole, when the petiole exists, are 
also 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 compressed, 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? Carefully describe the petiole 
of the Aspen. 
ie 2Q* 
