234 THE STATURAL HISTORT RETIEAV. 



word introduced into our science by Bentham. Indeed, he not 

 only sees no objection to tlieir recognition as such, but considers 

 it advantageous to unite all the allied forms into groups, corres- 

 ponding to and bearing the name of the original type. In the 

 book before us, he invariably notices these groups or types, and 

 gives the number of species into which each is separable 

 according to his observations. The Linnean type, from his point 

 of "vdew, loses its rank as a species, but remains as an assemblage 

 of true species all closely allied one to the other, and constituting a 

 natural sub-division of the genus. No true species, in the sense 

 in which M. Jordan understands that word, is distinguished by a 

 single conspicuous character. There is, for him, no such thing as a 

 well marked species (espece tranchee). Such characters distinguish 

 groups of species. It is only in a certain number of cases indeed 

 that the true species have hitherto been accurately distinguished 

 from each other, but as in every case in which a Linnean type has 

 been studied with due care it has *been analysed into several, it is 

 perfectly legitimate to conclude that it will be so in every 

 instance. 



We follow M. Jordan in his use of the expression Linnean type, 

 more for the sake of convenience than as intending to express our 

 belief that the Linnean species are in every case true to nature. 

 Every working botanist is well aware that, in the great majority of 

 cases, species as described in books are and must be empirical. 

 Their value varies in the case of each describer, with the nature of 

 his definition of a species, and perhaps in many cases according to 

 his estimate of the importance, or possibility, of accuracy of diagnosis, 

 and the consequent greater or less pains bestowed on them. In the 

 case of exotic plants, the descriptive botanist has rarely an op- 

 portunity of examining more than a few specimens, so that their 

 specific distinctness must be an inference from his knowledge of the 

 relative constancy of characters derived from the various parts of 

 the plants. This knowledge is acquired, in the first instance, by the 

 teaching of others, and by the study of their works, and afterwards 

 by the observation of the small number of species which it is 

 possible to study in detail. When Linna?us had a sufficiency of 

 materials, as in the case of the plants of his own country, and of 

 other parts of Europe visited by him, he seems to have applied his 

 great powers of generalization as successfully in this as in other 

 things, and to have brought together, under a common name, or as 



