432 JUGLANDACE^. [part ii. 



ORDER CLXXI.— ULMACE^. 



The principal genera are the Elm (Ulmus), 

 the Nettle-tree (Celtis), and the Zelkoua-tree 

 (^Planera). The flowers, though very small, are 

 pretty, from their opening in clusters before the 

 leaves ; and each has four stamens, with dark 

 purple anthers, and is furnished with dark 

 brown bracts. The fruit is a utricle, having a 

 single seed, encircled by a broad thin trans- 

 parent membrane. The leaves are rough, and 

 their sides are unequal at the base. The bark 

 of Elm trees is rough and deeply furrowed; 

 and the roots spread, instead of penetrating 

 deeply into the ground like those of the Oak. 



ORDER CLXXII PIPERACE^. 



The species are generally climbing plants 

 with perfect flowers, which are produced in 

 spikes, and are succeeded by one-seeded berries. 

 The genus Piper contains the common Pepper 

 (P. nigrum)^ the Betel (P. Betel), and several 

 other species. 



ORDER CLXXIII.— JUGLANDACE^.— (See Chap. XI. 

 P. 176.) 



The male and female flowers are distinct, but 

 on the same plant. The male flowers are pro- 



