IXTRODUCTION TO BOTANY. Iv 



characters peculiar to each, and furnished by the organs of 

 vegetation ; for example, the genus anagaUis, (pimpernel,) has 

 for its characters, a pecuhar corolla, and box-like fruit, (pyxi- 

 dium.) Now, all the species (or sorts) of this genus, anagal- 

 lis, must have these peculiar characters of corolla, and fruit ; 

 but the species Vfi[\ be distinguished from each other by the 

 forms of their stems, and leaves, &c. 



By uniting together genera in the same manner as species; 

 that is, by collecting into the same group those, which have 

 common and similar characters, we form orders, properly so 

 called, if we regard only a single character, such as the 

 number of stigmas, or the form of the fruit, &c. and natural 

 orders, or families, when for the formation of such an assem- 

 blage, there is required the concurrence of all the characters 

 that may be derived from the form, structure, and relative 

 situation of all the organs of the vegetables which are classi- 



D CD 



fied. A natural order, ox family of "plants, is, therefore, a 

 series or assemblage of genera, more or less numerous, which 

 have all the same characters in the organs of fructification. 

 Thus the cruciform (or crucifer^) family have all peculiar 

 characters: and all the genera of this family must have the 

 same characters, with some slight modifications, which will 

 serve to establish the differences of the genera, whose union 

 constitutes this family. 



The families being numerous, it has been found necessary 

 to distribute them into more or less numerous classes. We 

 will now mention the characters, employed by Jussieu for the 

 formation of his different classes. 



The classes are fifteen. The first divisions are marked by 

 the presence, or absence of the embryo in the seed. Hence 

 we have 1. emhryonate, 2. inemhryonate vegetables. 



The 1st. emhryonate, are distinguished according to the 

 number of their cotyledons ; 1st. into monocotyledons, or those 

 with one, and 2d. into dicotyledons, those with two or more 

 cotyledons. See Plate 12. Those without co/?//^fl'on5, are called 

 acotyledonous. 



That which serves for the establishment of classes properly so 

 called, is founded on the relative insertion of the stamens, or 



