306 Historical Notice of 



my, always displaying remarkable skill in the examination of ob- 

 scure genera, often ill described by their authors, and whose struc- 

 ture he refers to their true type with singular discrimination, as ap- 

 pears from his decisions having been almost invariably confirmed by 

 more recent observations. 



This revision forms the subject of fifteen memoirs, published 

 between the years 1804 and 1819, and embraces all the families of 

 the apetalous, and monopetalous dicotyledones, as well as the epi- 

 gynous, and hypogynous polypetales. 



Always desirous to complete the view of the vegetable kingdom 

 presented in his Genera Plant arum, and to make that work keep 

 pace with new discoveries and the progress of science, Jussieu pub- 

 lished successively other memoirs, in which he established new 

 genera, occasioned either by his having become better acquainted 

 with their structure since the publication of his original work, or 

 by the numerous discoveries resulting from recent scientific travels, 

 which had introduced into collections so many forms either wholly 

 new, or associating with genera hitherto insulated, and which he 

 had not therefore ventured to consider as the types of particular fa- 

 milies. It was thus that the author of the Genera, by being the 

 first to add to the edifice he had himself reared, showed that he 

 considered it susceptible of modifications and improvements ; for, 

 like every one of an elevated mind, he was aware that the sciences 

 are never stationary, and admitted that the natural method must 

 become more perfect in proportion as botany becomes more extended. 



In this way he added to the families already established in 1789, 

 those of the Loaseee, the Passiflorese, the Monimiese, the Lobeli- 

 aceee, the Polygaleae, and the Paronychieee. Finally, many of these 

 memoirs are occupied with the examination of obscure genera, whose 

 relations to known genera and natural families could be with diffi- 

 culty established ; of this description are the memoirs on the Pheli- 

 psea of Thunberg, the Hydropityon of Gsertner, many genera of 

 the Laurinese which ought to be united into one, and on different 

 genera of Loureiro. Perhaps there are few memoirs of great ex- 

 tent which evince more strikingly than these short notices, the ex- 

 tensive knowledge and discrimination of Jussieu : we perceive at 

 every instant how the appreciation of characters, their value, their 

 subordination, or their incongruity, proved a safe guide to him in 

 this difficult investigation. We there see disclosed, so to speak, the 

 method he followed in ascertaining the alliances of numerous exotic 

 genera, often very imperfectly known, and which he has almost al- 

 ways succeeded in classing correctly in his immortal work. 



