Kinds op leaves in reference 

 to the medium 



KINDS OP LEAVES. 21 



1. KINDS OF LEAVES IN REFERENCE TO THE MEDIUM. 



The leaf may exist either exposed to the air, as in the 

 ordinary case, or submersed in water, as in the Sasamo and 

 Midzuobako (Ottelia japonica), or buried in the soil, as in 

 the subterranean stems of the Oniyuri (Fig. 12) and Jaga- 

 taraimo (Fig. 14). 



That which exists exposed to the air is called the Aerial 

 Leaf ; that which exists submersed in water, the Aquatic 

 Leaf ; and that which exists buried in the soil, the Subter- 

 ramean Leaf. 



Aerial Leaf. 

 Aquatic Leaf. 

 Subterranean Leaf. 



2. KINDS OF LEAVES IN REFERENCE TO THE FUNCTION. 



Ordinary leaves are green, mostly flattened, and their 

 functions are not related to reproduction. Such leaves 

 are called Foliage Leaves. There are other leaves which 

 have reproductive or protective functions, or which are 

 insectivorous, or merely rudimentary, or varied in some 

 other way. These are called Modified Leaves. 



KINDS OF LEAVES IN REFERENCE] Foliage Leaf. 

 TO THE FUNCTION 1 Modified Leaf. 



A. THE FOLIAGE LEAF. 

 The Foliage Leaf is always green, mostly flattened, and 

 does not produce reproductive organs ; it has usually such 

 two surfaces as one is turned upwards and the other down- 

 wards. 



1. PARTS OF THE FOLIAGE LEAF. 



In the most highly developed foliage leaf, its lower portion, 

 including the base, is more or less dilated so as to embrace 

 the stem, from which it springs ; its upper portion, includ- 



