132 PRINCIPLES OF BOTANY. ETC. 
bear in the first year leaves, in the second 
' flowers and seeds, and then die: these are 
called biennials, (planie biennes.) 
6. Under-shrubs, (sufrutices): im these the stem 
perishes annually, but the root remains. 
¢. Shrubs, (frutices): of these the stem con- 
tinues many years, and is divided below into 
branches. 
d. ‘Vrees, (arvores): of these the stem endures 
for many years, and is divided at top into 
branches. 
Climate and culture have great influence on these 
divisions ; so that often trees and shrubs insensibly 
run into one another. 
§ 123. 
Before we proceed to treat of the different sys- 
tems, it is necessary to explain what 1s meant by 
Class, Order, Genus, Species and Variety. ; 
A. System is rst divided into classes and orders. 
In each system a certain part of plants, such as the 
flower, the fruit, &c. is assumed as the foundation, 
and upon that, classes, orders, and genera are con- 
structed. When a particular investigated character 
is common to many plants, these plants make a 
Class, (classis), Should some of the plants, . be- 
side the particular character of the class, agree in 
another character, these form an Order, (ordo). 
And if a few of the plants, which already agree 
in two of the characters, are found to possess others 
in common, these are called a Genus. . Each of the 
plants. in this last division is called a Species. It 1s 
A; necessary — 
