Arrangements of Plants. l8l 



and in what terms they are to bp described, we find only a 

 series of appellations, mostly derived from some particular 

 genus of plants which is supposed sufficiently predominant to 

 give a name to the order, and which order includes certain 

 other genera which appear to be related to it*. If, however, 

 we are dissatisfied with this mode of distinction, as affording 

 us no determinate idea, nor giving us any clue to discover how 

 such order is formed, we can only have recourse to a com- 

 parison of the descriptions placed at the head of each of the 

 orders of which each class is composed. That the Jasmineae 

 may form a part of the same natural class as the Gentianse, 

 although their relation be not very apparent, may be admitted ; 

 because they equally germinate from two cotyledons, and have 

 each a monopetalous corolla situated beneath the germen; 

 but when we ask why diese genera are not also of the same 

 order, we must seek for an answer in the description prefixed 

 to each order in the body of the work ; until by a careful per- 

 usal and comparison of these descriptions, which in many re- 

 spects agree, we are at length enabled to determine in what 

 the difference between a Jasmine and a Gentian, a Laurus or 

 an Atriplex, really consists. In this secondary part of the 

 system it will therefore scarcely be denied that the advantages 

 of perspicuity and precision are wholly on the part of Linnaeus, 

 whatever may be the case as to the natural order of the plants ; 

 in which respect, however, it is by no means clear that Jussieu 

 possesses any superiority over his predecessor. 



From classes and orders we descend to genera, in the de- 

 tern)ination of which the chief difficulties of the science con- 

 sist; but as in some of the orders the number of genera is very 

 great, it has been found indispensably necessary to divide such 

 orders into sections, so as to place each genus in its proper 

 relative situation, and break in as little as possible upon their 

 natural or apparent affinities. This Linnaeus and his subse- 

 quent editors have endeavoured to do by a kind of collateral 

 arrangement placed at the head of each class, though not 

 strictly conformable to the rest of the system. For the discri- 

 mination of these sections there remained ample materials. 

 The stamina and pistils had indeed already been employed in 

 characterizing the classes and orders; but the corolla, as well 

 with respect to the number of its petals as its form and situa- 

 tion, the calyx, the receptacle, the germen, the stigma and the 

 fruit, all oflered important marks of discrimination, which 

 liave been made use of so as greatly to assist the student, al- 



• Tims the 4tli order of the Htli class is dciioniinateil Jnsmiiira; and in- 

 cludes the genera of Muytcniis—Nyclanlhes— Lilac— Iluhc— Fraxinus— 

 Chionanthus— OIca— I'hillyrca— Mogorium — .lasmiiiiiin and Ligiistruni. 



though 



