354 CLASSIFICATION. 



Apple and Thorn on the other, exhibit a closer relationship than 

 that which connects them all in one common group. Hence they 

 are respectively distinguished into groups of a rank intermediate 

 between genera and orders, which are variously termed SUBOR- 

 DERS, or TRIBES.* 



676. Classes are groups of orders, associated in a similar manner 

 from some higher point of view. SUBCLASSES bear the same rela- 

 lion to classes that suborders do to orders. 



677. By this regular subordination of groups, the various degrees 

 of relationship among plants may be expressed ; and upon this Sys- 

 tematic Botany essentially depends. Only four of these divisions 

 are universally employed, namely, Classes, Orders, Genera, and 

 Species : these are common to all methods of classification, both 

 in the animal and vegetable kingdoms, and are always arranged 

 in the same sequence. But a more elaborate analysis is often 

 requisite, on account of the large number of objects to be arranged, 

 and the various degrees of affinity to be expressed ; when the ad- 

 ditional members, and if need be several others, are introduced ; 

 as in the following descending series, beginning with the primary 

 division of natural objects into kingdoms, and indicating by small 

 capitals those of fundamental importance and universal use. 



KINGDOMS, * 

 Series, 



CLASSES, 



Subclasses, 



ORDERS, or FAMILIES, . 

 Suborders, 

 Tribes, 



Subtribes, 

 GENERA, 



Subgenera, 

 SPECIES, 



Varieties. 



678. Characters, An enumeration of the distinguishing marks, 



* When the groups which an order embraces are distinguished by charac- 

 ters of nearly equal value with those commonly employed for orders them- 

 selves, they are termed SUBORDERS. Thus, the Plum, Cherry, Apricot, 

 Peach, &c., form one suborder of Rosacese; the Raspberry, Blackberry, 

 Strawberry, Cinquefoil, with the Rose and other genera, constitute another 

 suborder ; and the Apple, the Q,uince, Thorn, &c., a third. The name of 



