328 LINNiiJUS AND THE JUSSIEUS 



criticism or important amplification. Jussieu's Genera 

 Plantarum, which had appeared in 1789, is barely 

 mentioned. Some description of each order and of its 

 principal genera is attempted, but no distinctive char- 

 acters are given, for reasons which will shortly appear. 



Affinity was of course not yet traced to descent from 

 common ancestors. Linnaeus had compared species to 

 the provinces of a map,' a comparison which not only 

 suggests the regular subdivision of primary into 

 secondary, secondary into tertiary groups, and so on, 

 but also the possibility that a group of any rank may 

 directly link more than two others. Giseke exhibits 

 his own " genealogico-geographical map," and this map 

 shows fungi, algae, mosses and ferns, leading up to 

 conifers and amentacese on one side, to palms and other 

 monocotyledons on the other ; it is a dim forecast of a 

 phylogeny of plants. 



By far the most interesting passage in the book is the 

 report of a conversation between Linnaeus and Giseke, 

 which belongs to the year 1771. The conversation has 

 been quoted in Whewell's History of the Inductive 

 Sciences, from which the following abridgement is 

 made (3rd ed.. Vol. Ill, pp. 269-271) : — "Giseke began 

 by conceiving that an order must have that attribute 

 from which its name is derived — that the Umbellatae 

 must have their flower disposed in an umbel. The 

 'mighty master' smiled, and told him not to look at 

 names, but at nature. 'But,' (said the pupil) 'what is 

 the use of the name, if it does not mean what it pro- 

 fesses to mean ? ' ' It is of small import,' (replied 

 Linnaeus), ' what you call the order, if you take a proper 

 series of plants and give it some name, which is clearly 



' " PlantES omnes utrinque affinitatem monstrant, uti Territorium in Mappa 

 geographioa." Phil. Bot. , %'n . 



