242 



PARTS OF THE LEAF. 



[BOOK i. 



many Monocotyledonous plants, Ferns and Mosses, no arti- 

 culation exists, and the base of the leaf only separates from 

 its parent stem by rotting away. 



48 



This difference of organisation has given rise to a distinc- 

 tion, on the part of Oken, between the articulated leaves of 

 Dicotyledons and the inarticulated leaves of Monocotyledons 

 and Acotyledons : the former he calls true leaves, and dis- 

 tinguishes by the name of Laub; the latter he considers 

 foliaceous dilatations of the stem, analogous to leaves, and 

 calls Blatt. 



A leaf consists of two parts ; namely, its stalk, which is 

 called the petiole (fig. 48. ), and its expanded surface, which 

 is called the blade or lamina (fig. 48. c, b, d): in ordinary 

 language the latter term is not employed, but in very precise 

 descriptions it is indispensable. 



The point where the base of the upper side of a leaf joins 

 the stem is called the axil; anything which arises out of that 

 point is said to be axillary. If a branch or other process 

 proceeds from above the axil, it is called supra-axillary; if 

 from below it, infra-axillary. 



The scar formed by the separation of a leaf from its stem 

 is sometimes called the cicatricule. The withered remains of 

 leaves, which, not being articulated with the stem, cannot fall 

 off, but decay upon it, have been called reliquice or induvice, 

 and the part so covered is said to be mdumate. 



