NOTICES OF BOOKS. 185 



data, and that these chapters are not all treated in the same manner or 

 spirit that the previous ones are. 



Book III. Botanical Geography. 



Chapter 20. The opening chapter discusses the characters of the 

 vegetation of a country under a series of articles ; the first of them is 

 devoted to the nature of these characters, considered by themselves. 



1. Characters relating to the classes^ treats of — 1^ the proportion of 

 Pheenogams to Cryptogams ; this inquiry is pronounced to be very 

 useless* in the present state of science ; — 2, that of Dicotyledons to 

 Monocotyledons is, we are informed, little better worth attention, owing 

 partly to causes which M. de Candolle considers to be overlooked by 

 authors who are ordinarily very judicious ;t as because the numbers of 

 Ci/peracece and Graminece in cold countries, and of Orchidem in hot, are 

 not usually well ascertained ; because the proportion of Monocotyledons 

 is smaller in a large area than in a small part of that area (owing to 

 the greater extension of the species of Monocotyledons); and because 

 the Monocotyledons belong to very different Families in different parts 

 of the world. t 



2. On the proportions of groups of greater value than Natural Orders^ 

 and less than Families : — This inquiry is also considered to be of littl 

 value. 



M. de Candolle justly remarks that it is of high importance to ascer- 

 tain the relative amount of herbaceous and woody plants in a Flora; of 

 annuals, biennials, etc., and of other characters, such as succulence, 

 persistence of foliage, aud number of plants with compound leaves, |1 

 because all these give a character to every vegetation. The desirability 



* This unqualified denunciation of what has appeared to many of the first botanists 

 of the day a curious and interesting subject of inquiry, rather takes us by surprise. 

 That the numerical relations of Cryptogams to Phsenogams often affords a most 

 striking illustration of corresponding difterences in climatic conditions, is of itself 

 sufficient proof of the subject having some interest. 



t These causes, though put forward as if new, are by no means so ; all of them 

 have been discussed in works relating to the subject in question, and some of them 

 are so trite and obvious to any observer, that it is going too far to suppose them 



Oferlooked where they are not put forward. . 



t The force of this objection we cannot at all perceive, nor why a similar one 



should not be applied to Dicotyledons. ^, » . .i • - ^ ^ 



II The amount of plants with compound leaves we hold to be, m this point of 

 view, very immaterial, though so insisted upon by some naturalists; they rarely 

 give a character to the vegetation, and, except in individual cases, the ravellcr cannot 

 tell, at a few yards' distance, whether a tree has simple or compound leaves. 



VOL. V^III. * *" 



