Antoine Laurent de Jussieu. 299 



ing year, on the new arrangement of plants in the royal garden at 

 Paris, we find, for the first time, the fundamental principles of the 

 natural method explained with perspicuity and precision. We there 

 find a just appreciation of the grand principles of subordination of 

 characters, and their unequal value ; a principle unknown to Linne 

 and Adanson, evidently recognized by Bernard de Jussieu, but of 

 which Laurent de Jussieu was the first to perceive the full import- 

 ance, and he afterwards applied it with singular judgment. 



Thus, in the first of the above-mentioned memoirs, we find this 

 passage : 



" We have seen, by some general principles developed in this 

 memoir, the affinity which exists between the parts of fructifica- 

 tion ; in this affinity diflferent degrees are perceptible : all these 

 characters have not the same value, or the same efficacy in uniting 

 or separating plants. Some are primitive, essential, and invariable, 

 such as the number of the lobes of the embryo, its situation in the 

 grain, the position of the calyx and of the pistil, the attachment of 

 the corolla and stamens; these serve for the principal divisions. 

 The others are secondary ; they are sometimes variable, but never be- 

 come essential, unless when their existence is connected with that of 

 some of the preceding, and it is their assemblage which distinguishes 

 the families." 



Such, then, from the date of 1773, were the fundamental prin- 

 ciples by which Antoine-Laurent de Jussieu was guided in drawing 

 lip the Genera Plantarum. They are expressed with much preci- 

 sion ; and if he sometimes deviates from them, it may be perceiv- 

 ed that he does so as a concession to facility of study, or to the old 

 systems, rather than from real conviction. Thus in the memoir 

 read in 1774 on the new arrangement in the Garden of Plants, he 

 has evidently departed from the rigorous principle of the insertions, 

 as Bernard de Jussieu had admitted them in the catalogues of Tri- 

 anon, by dividing the dicotyledones into apetales, monopetales, and 

 polypetales ; but we have only to read his memoir to perceive, that 

 his only object was to multiply the great classes, and to establish 

 some relations between the new order and the method of Tourne- 

 fort which it replaced, and which was generally known, not only to 

 the pupils, but to the majority of the botanists of that era. We 

 must not therefore lose sight of the origin of this part of Jussieu's 

 classification when we wish to appreciate the method followed in 

 the Genera Plantarum, which does not sensibly differ from it. 



From this period up to 1785, Antoine-Laurent de Jussieu always 

 arranged the plants in the botanic garden according to this method. 



