LEAVES 



163 



rounded at the apex, not much longer than broad, and 

 broadest above the center, as in chokecherry; it is deltoid 

 when the outline is nearly triangular, as in poplar ; it is cuneate 

 when the apex is broad, nearly truncate, and the margins 

 taper gradually into the petiole, as in barren oak. 



FIG. 98. Venation of Leaves. Palmately parallel veined. 1, Wild yam 

 (Dioscorea villosa) ; 2, two-leaved Solomon's seal ( Unifolium canadense) ; 

 pinnately parallel veined; 3, garden canna (Canna sp.); 4, (Dracema sp.), 

 palmately netted veined; 5, red maple (Acer rubrum), Pinnately netted veined; 

 6, chestnut (Castanea dentata); 7, witch hazel (Hamamelis virginiana) . 



Compound Leaves. A leaf is compound when the blade 

 is separated into two or more parts or leaflets. When the 

 leaflets are arranged along a stalk or rachis the leaf is pin- 



