VENATION. 23 



of the Momiji (Acer palmatum) (Fig. 18) ; in some the 

 petiole is absent as in those of the Ine (Fig. 10) ; and in 

 others both the petiole and leaf-sheath are absent as in 

 those of the Doku-utsugi (Coriaria japonica) (Fig. 19). 



Paets op the foliage leaf 



( Lamina. 

 Petiole. 

 Leaf -sheath. 



a. The Lamina. 

 The Lamina is the most important part of the foliage 

 leaf and is usually expanded and flattened. 



1. PARTS OF THE LAMINA. 



The organically lower end of the lamina, where it is 

 connected with the petiole in a well developed leaf, is called 

 its Base ; the opposite or organically upper end, its Apex ; 

 the lines connecting the two extremities, its Margins ; and 

 the portion enclosed within the margins, its Body. (See 

 Fig. 16.) 



PARTS OF THE LAMINA' Body— Margins. 



Apex. 



2. VENATION OR NERVATION. 



The skeleton of the lamina is composed of woody thread- 

 like structures which are called Veins, and the modes of 

 their distribution are called Venation. Large veins, pro- 

 ceeding from the base to the apex of the lamina, are called 

 Bibs, and the most prominent central vein is called the 

 Midrib. 



The veins are distributed either anastomosing so as to 

 form a kind of network as in the leaves of the Sakura (Fig. 

 16) and Momiji (Fig. 18), or more or less parallel to one 

 another as in the leaves of the Ine (Fig. 10) and Maidzuruso 



