NATURAL SYSTEM. 201 
__ 689. As has been already mentioned, the parts of the 
_ flower and fruit are those which are best adapted for-the con- 
-Struction of a scientific arrangement. The natural system is 
composed of from one to two hundred orders ; that is, there 
_ 4re upwards of a hundred families of plants which differ from 
_ ach other in some well marked and important particulars. 
But botanists do not content themselves with observing the 
natural arrangements of plants in families. They go a step 
arther, and endeavour to arrange these families in divisions, 
sections, classes, &c., founded upon some parts of importance 
in the structure of plants. And accordingly, when it is found 
that a family of plants is placed in a particular situation in” 
ng method, we have acquired a knowledge of some leading 
_ Points in the structure of the plants in that family. These 
families themselves must be classified, as well as the plants 
which they contain, that we may be enabled by one or two 
characters to find them easily. : 
690. The first grand division is into those which have 
flowers, sexual organs, and a seed with an embryo, and those 
hich are destitute of these organs. The first are the 
Phenogamia, called also Vasculares, Embryonate, or Coty- 
: The second are the Cryptogamia, called also Cel- 
ulares, Inembryonate or Acotyledonez. 
CRYPTOGAMIA. 
691. The orders in this division are few and easily remem- 
: they are often set down without any further arrange- 
PHENOGAMIA. 
692. In this division there are a great number of different 
orders, which are arranged in sections or classes. 
893. The Phenogamia or Cotyledonee are, in the first — 
Place, divided into two large sections: 1. The Monocotyle- 
donee or Endogene ; and, 2. Dicotyledonew or Exogense. — 
