INTRODUCTION, 



Ixvii 



and the rings by which the sails of vessels are 

 attached to the mast. "When burnt, it consumes 

 slowly, and gives out a great heat ; hence it is 

 considered the best wood for fuel. The various 

 kinds of Hickory timber, when stripped of their 

 bark, are said to be so much alike, as not to be 

 distinguished by the most practised eye. The 

 structure of the nut closely resembles that of the 

 Walnut, but it is not deeply furrowed like the 

 fruit of the latter tree. Engelhardtkt spicata, a 

 Java tree, attaining a height of 290 feet, is used 

 for cart-wheels, which are cut out of a single hori- 

 zontal block. Most of the trees of this order 

 abound in a watery resinous juice. 



AMEXTACE^. 



Amentaceous tribe. 



This order derives its name from amentum^ a 

 catkin, the term used by botanists to designate the 

 form of inflorescence when a number of flowers 

 destitute of calyx and corolla are arranged along a 

 common stalk, which falls off in one piece, either 

 after flowering or after the ripening of the fruit. 

 The plants of which this important order is com- 

 posed agree in bearing their flowers in catkins, 

 but nevertheless differ so materially in other 

 respects, that they have been subdivided into dis- 

 tinct sub-orders or groups. Of these some con- 

 tain no British genera : those in which indigenous 

 examples occur, are — 



