134 USE OP BOTANICAL NAMES. 



necessary to resort to this instrument, in order to establish the natui-al 

 ••elations of plants.* 



Having considered the meaning of individual, species, genus, and 

 family, and of the characteristics by which these are grouped toge- 

 ther, let us take a general view of the subject. It is evident, by the 

 formation of species, genera, and families, that every species should 

 offer the essential characters of the family and genus to which it be- 

 longs ; while the marks which distinguish this species from anuthei 

 species of its genus, will be such as do not belong to the w-hole ge- 

 nus or family. The different genera in families are also distinguished 

 by characters which do not belong to the whole family ; every indi- 

 vidual, then, will possess its specific character, its generic charwcter, 

 and its family character. 



The specific character is less important than the generic, as it is 

 mostly founded on the characters of the organs of vegetation, which 

 we have seen are isolated, and less important than the coexistent 

 characters. We often find, in the analysis of plants, a great diriiculty 

 in determining their species, from the want of definite marks of dis- 

 tinction. 



Generic characters are mostly of the coexistent kind, and are 

 more valuable than the specific characters. The distinctions of gen- 

 era are usually much more apparent than those of species ; as a 

 rose can be more easily distinguished from a pink, than one species 

 of rose from another species. 



Families are grouped together by marks of resemblance found in 

 genera. These family characters are, of all others, the most impor- 

 tant. In the artificial classes and orders we depend on what we have 

 before termed factitious characters. In species, genera, and fami- 

 lies, the essential characters are also natural characters. 



LECTURE XXIII. 



USE OF BOTANICAL NAMES — ARTIFICIAL CLASSES AND ORDERS CONSIDERED IN 

 GROUPS — CLASSES MONANDRIA AND DIANDRIA. 



You have been taught the principles on which the Linncean sys- 

 tem is founded; we shall now examine each class separately, with 

 the orders it contains, and the most remarkable plants and natural 

 famiUes which we shall meet with in our progress through this system. 



We have observed, that this appears to be the best method yet 

 discovered of classing new plants, and of ascertaining the botanical 

 names of those which are already known by common names. If, 

 in all countries, the common names were alike, there would be no 

 need of any other; but the names of plants vary in different lan- 

 guages as much as other terms. Even in the same country, and 

 often in the same neighbourhood, the common names of plants are 

 different ; but botanical names are the same, in all ages and coiu> 



* The foregoing rules and observations respecting characters for classification, are 

 chiefly translated from Mirbel's "i?/eme«s de^o/amg^e." " i 



General view of the subject of classification— Which is the more important, the spe- 

 cific or generic character?— Why are generic characters most valuable?- How are 

 families grouped together?— On what do artificial orders depend?— What are the es- 

 sential characters in species, genera, and families ?— Why are not the common namea 

 3t plants suflBcient for all purposes? 



