The Rev. P. Keith on the Classification of Vegetables. 39 



posita, as published in 1789, is something more than a mere 

 catalogue, and M. A. Laurent de Jussieu is something more 

 than its mere editor : he is, in fact, its author. He could not 

 have been the editor of the writings of one who wrote nothing. 

 He could not have gathered all that was necessary to the com- 

 position of the Genera Plantarum from a few occasional con- 

 versations with his uncle. He could not have produced that 

 chef-d'oeuvre of botanical and logical arrangement without years 

 of close and previous study. Besides, many facts necessary 

 to its final completion were not even known at the time of his 

 uncle's death. Hence we see why the work was not ready for 

 publication before 1 789. Hence we see what portion of it is 

 to be ascribed to the uncle and what to the nephew ; and we 

 must beware of detracting from the merits of the one for the 

 purpose of enhancing the merits of the other. 



In this profound and elaborate work the subjects of the ve- 

 getable kingdom are distributed into three grand groups, Aco- 

 tyledonous, Monocotyledonous, and Dicotyledonous plants. 

 The sections are founded on the peculiarities of the corolla, 

 and the classes on the insertion of the stamens. Still the ad- 

 vocates of the sexual system say that the method of Linnaeus 

 is not more artificial than that of Jussieu, whom they accuse 

 of founding his sections merely on number, as Linnaeus founds 

 his classes and orders *. But it should be recollected that it 

 is under very different circumstances. Linnaeus selects a single 

 species of organ, — the stamens — and all plants furnished with 

 the same number of stamens are thrust into the same class 

 without reserve, let their natural affinities be what they will. 

 Indeed, natural affinities are not so much as looked for. Thus 

 you have the Asperifoliae and the Umbelliferae, the Bugloss 

 and the Bulbocastanum, associated in the same class, without 

 any connecting link, apparent or presumptive, beyond that of 

 their having the same number of stamens; and thus you are 

 under the necessity of separating the single genus Anthoxan- 

 thum from the natural family of the Grasses, because it happens 

 to have but two stamens to its flower instead of three, which 

 the rest of the grasses have. In the class Dodecandria the 

 stamens should be twelve, but by special allowance they may 

 be from eleven to nineteen. The orders exhibit the same in- 

 congruities. In Diandria Monogynia, you have Enchanter's 

 Nightshade and Common Ash placed side by side ; and in Pen- 

 tandria Digynia, you have Cuscuta and Ulmus. The styles of 

 Icosandria Pentagynia are by special privilege also allowed to 

 be from two to five. Yet these incongruities are not to be se- 



• Roscoe on Arrangements, Linn. Trans., vol. xl. [or Phil. Mag. and 

 Annals, N.S., vol. vii. — Edit.] 



