EXPLANATION OF TERMS. 



I. 



TREES, as distinguished from shrubs, are those species 

 which, as the rule, spring from the ground with a single, 

 branching trunk. 



II. 



A LEAF is : 



(i) Simple, when it is of one piece. (Fig. a, Willow 

 Oak.) 



(2) Compound, when there are two or more entirely 

 separate pieces (called leaflets} on the one leaf-stem. 

 (Figs, b and c, Dwarf Sumach and Horse Chestnut.) 

 See note 2. 



COMPOUND LEAVES are : 



(1) Feather-shaped, when the leaflets are placed 

 along the sides of the leaf-stem. (Fig. b.) 



(When the compound leaf ends with a pair of leaflets 

 it is even-feathered ; when it ends with one leaflet it is 

 odd-feathered^) 



(2) Hand-shaped, when all the leaflets radiate from 

 the end of the leaf-stem, like fingers from the palm of 

 the hand. (Fig. cJ) 



NOTE i. Compound leaves may be once, twice, or three times compound. 

 NOTE 2. The leaflets of a compound leaf can be distinguished from a simple 

 leaf by the absence of leaf-buds from the base of their stems. 



238 



