368 CLASSIFICATION. 



or two-lipped corolla (511), which nearly all the species exhibit; 

 Cruciferce, which have their four petals disposed somewhat in the 

 form of a cross, &c. But more frequently, and indeed as a gen- 

 eral rule, the name is formed from that of some leading or well- 

 known genus, which is prolonged into the adjective termination 

 acea. Thus, the plants of the order which comprises the Mallow 

 (Malva) are called Malvacea ; that is, Planta Malvacece, or, in 

 English, Malvaceous plants : those of which the Rose (Rosa) is 

 the well-known representative are Rosacece, or Rosaceous plants, 

 &c. This termination in acece, being reserved for orders, should 

 not be applied to suborders or tribes, which usually bear the name 

 of their principal or best-known genus in an adjective form, with- 

 out such prolongation. Thus the genus Rosa gives name to a par- 

 ticular tribe, JRosete, of the order Rosacece ; the genus Malva to the 

 tribe Malvece of the order Mdlvacece, &c. 



699. The number of genera in an order is quite as indefinite as 

 that of the orders in a class, or other great division. While some 

 orders are constituted of a single genus, as Equisetacece, Grossu- 

 lacese, &c. (just as many genera contain but a single known spe- 

 cies), others comprise a large number of genera ; nearly nine 

 hundred being embraced in the last general enumeration of the 

 Composite. 



700. The names of genera are Latin substantives, in the singu- 

 lar number, and mostly of Greek or Latin derivation. Those 

 which were known to the ancients generally preserve their classi- 

 cal appellations (Ex. Fagus, Primus, Myrtus, Viola^ &c.) ; and 

 even the barbarous or vulgar names of plants are often adopted, 

 when susceptible of a Latin termination, and not too uncouth ; for 

 example, Thcea and Coffcea, for the Tea and Coffee plants, Bam- 

 busa for the Bamboo, Yucca, Negundo, &c. But, more common- 

 ly, generic names are formed to express some botanical character, 

 habit, or obvious peculiarity of the plants they designate ; such as 

 Arenaria, for a plant which grows in sandy places ; Dentaria, for 

 a plant with toothed roots ; Lunaria, for one with moon-shaped 

 pods; Sanguinaria, for the Blood root ; Crassula, for some plants 

 with remarkably thick leaves. These are instances of Latin deriv- 

 atives ; but recourse is more commonly had to the Greek language, 

 especially for generic names composed of two words ; such as 

 Menispermum, or Moonseed ; Lithospermum, for a plant with stony 

 seeds; Melanthium, for a genus whose flowers turn of a black or 



