22 



MORPHOLOGICAL BOTANY. 



ing the apex, is usually expanded and flattened; and its 

 middle portion is narrower and commonly semicylindrical. 

 The expanded upper portion is called the Lamina or Blade, 



Fio. 16. 



a 



Pig. 16. — Herbaceous, annual, dentate, and pinnately veined leaf of the 

 Sakura. a Lamina ; b petiole ; o leaf-sheath -with stipules ; d glands. 



the narrower middle portion the Petiole or Leaf-stalk, and 

 the sheath-like lower portion the Leaf-sheath. (See Fig. 16.) 

 These three portions are not, however, developed in all 

 leaves : in some leaves the leaf-sheath is absent as in those 



