82 GENERA. 



By taking into the generic character a greater or 

 less numher of marks, Linnseus himself makes several 

 kinds of generic characters. The most important are 

 the Natural and the Essential. 



1. The Natural character comprehends every possi- 

 ble mark, common to all the species of one genus ; is 

 an enumeration of all the particulars in which their 

 fructifications agree. 



2. The Essential character consists of an enumera- 

 tion of those marks onl), which distinguish the genus 

 from all others. This last, is the kind of generic char- 

 acter now universally adopted, and indeed the only one 

 in common use. The excellence of the essential char- 

 acter consists in its brevity and perspicuity. In ten 

 or twelve words, it frequently makes know the dis- 

 tinguishing marks. 



The natural character is much more lengthy, and 

 does riot direct the attention, particularly, to those es- 

 sential marks which distinguish the genus. It is used 

 by Linnaeus in his Genera Plantarum, a work now near- 

 ly superseded by the essential characters* in his Systema 

 Vegetabilmin 9 and therefore, in some measure laid aside. 

 Both the Natural and Essential characters are put 

 down in the Cyclopedia. 



Observations. The study of genera cannot be too strongly re- 

 commended to the young Bo anist. The science of Botany may 

 be said to corsist principally in a knr wedge of them, and the 

 whole use of the Classes and Orders, is to afford a facility, by 

 which to arrive at this knowledge. When a Botanist has become 

 acquainted with a single species of a genus, and by examining its 

 flower and fruit, fixed in his mind the character of the genus, he 

 is enabled to recogrT.ze all the other species, which, in some Di- 

 stances, are hundreds, wherever he may meet With them. TI is 

 serves to give some idea of the pleasures and advantages of a 

 knowledge of genera. 



But it is not from books alone that this knowledge is to be obtain- 

 ed ; the student should study plants themselves ; he should make na- 

 ture principal, and books auxiliary In Botany, as well as in 

 every other branch of Natural Hi-tory, the objects themselves 

 should be studied, and books be used as a mere assistance. 



