MARGIN OF LEAVES. 129 



we find leaves, alternately or oppositely pinnate. If 

 these leaflets alternate with others of a smaller size, 

 as in Agrimony, the leaf is interruptedly pinnate. Fig. 44. 



When a leaf atalk is divided, and the leaflets arise 

 only from the superior side of its two branches, the 

 leaf is said to be Pedate, Fig. 46, Viola pedata and 

 Arum dracontium are examples. 



When a petiole is divided, and each division supports 

 a compound leaflet, it is said to be Decompound. Such 

 leaves are usually Biternate, Fig. 50, or Bipinnate. 



When the secondary branches of a petiole support 

 compound leaflets, it is said to be Thrice compound, and 

 if the leaflets are ternate, as in Panax trifolium, the 

 leaf is thrice ternate. 



5. SUMMIT. 



The Summit of leaves is Acute, as in the Willows, 

 or Acuminate being still more slender and pointed, as 

 in the Lombardy Poplar, or it is obtuse as in the round, 

 ovate and wedge shaped leaves, which terminate in the 

 segment of a circle. 



The Truncate leaf terminates abruptly, as if its ex- 

 tremity had been removed by a transverse incision ; 

 and the Tulip tree, Fig. 48, is a good example. 



If the extremity of a leaf is tipped with a bristle-like 

 point, as in Marsh Rosemary, it is said to be Mucron- 

 ate, and if it is tipped with a tendril it is Cirrhose. 



If it has a small acute notch at its summit, it is Emar- 

 ginate, but if the notch be broad and shallow it is 

 Retuse. 



6. MARGIN. 



The margin of leaves i9 Entire, as in Lilies ; Spinous 



