36 MORPHOLOGICAL BOTANY. 



b. The Petiole. 

 The Petiole is that portion of a leaf, which stands be- 

 tween the lamina and the sheath and is usually semicylin- 

 drical being branched or not. Not unfrequently the petiole 

 presents foliaceous margins, as in the Yudzu (Citrus auran- 

 tium) (Fig. 47) and Nurude (Bhus semi-alata), and is then 

 said to be Winged or Alate. 



Duration of the Petiole. — The duration of the petiole 

 is mostly similar with the lamina which it bears, but in a 

 few cases it remains on the stem after its lamina falls off, as 

 in the Aokatsura (Sabia japonica) . 



c. The Leaf-sheath. 

 The Leaf-sheath is that portion of a leaf, which stands, 

 below tbe petiole and embraces the stem more or less assum- 

 ing a tubular or sheath-like form. It is very much developed 

 in Grasses, Sedges, and many Umbelliferae as the Nodake 

 (Angelica decursiva), Ashitaba (A. kiusiana), etc.; in 

 Grasses it is usually split in front, but in Sedges it is mostly 

 closed. 



It is often provided with two small leafy appendages 

 which are situated one on each side of the leaf-sheath, as in 

 the Sakura (Fig. 16) and Noibara (Bosa multiflora) . Those 

 leafy appendages are called Stipules. 



Duration oe Stipules. — The duration of stipules varies 

 in different leaves : in some leaves, as those of the Mokuren 

 and Sakura (Fig. 39), they fall off very soon ; while in 

 others, as those of the Noibara and Yendo (Pisum sativum) r 

 they remain attached as long as the laminse. The stipules 

 of the former kind are said to be Deciduous, and those 

 of the latter Persistent. 



