Bibliographical Notices. 199 



The Flowering Plants and Ferns of Great Britain : an attemjit to 

 classify them according to their Geognostic relations. By J. G. 

 Baker. Loudon. 1855. 



This tract is an enlarged form of a paper communicated to the 

 British Association at its recent meeting at Glasgow. Its subject is 

 of much interest in the study of the geographical distribution of 

 plant?:, and has not received so much attention as it seems to deserve. 

 Hitherto botanists have endeavoured to determine the causes of the 

 migration, or creation, of the plants found in diflFerent districts, by 

 attending to the collocation of the places where they grow, rather 

 than from a consideration of the strata forming the crust of the 

 earth. Mr. Baker has therefore done good service to science by this 

 attempt at determining the geological causes that may be supposed 

 to have had an influence. It is not to be expected that this attempt 

 should be altogether satisfactory in its results, for many more obser- 

 vations than we at present possess are wanted before certain conclu- 

 sions can be attained. 



He arranges the strata into two great groups: (1) The dysgeo- 

 genous, " which are disintegrated with difficulty, and yield only a 

 feeble detritus." *' They absorb moisture readily, and furnish 

 stations characterized by their comparative dryness," and contain a 

 large proportion of carbonate of lime. And (2) the euyeogenous, 

 "which abrade easily, and yield an abundant superficial detritus, 

 which may be either of a sandy or clayey nature. They are com- 

 paratively impermeable, and consequently hygroscopic upon a grand 

 scale, furnishing damper stations" than the other group. He 

 then shows how these classes of strata are distributed through 

 Great Britain, and endeavours to arrange the native plants into either 

 those which are spread over the whole country, or confined to one or 

 the other of the groups. We think that he has been tolerably suc- 

 cessful, although we should not in all cases agree with him. Indeed, 

 it seems probable that it is rather the superficial soil that must 

 often be taken into account, than the underlying strata. The soil 

 of large districts noted as clay on geological maps, may, and actually 

 has, a strongly calcareous character from the presence of adjacent 

 rocks, such as chalk, and accordingly possesses a flora containing 

 many of the species usually called calcareous, or chalk plants, and 

 does not produce others conmionly foimd on a clayey soil, but which 

 dislike the presence of lime or chalk. Mr. Baker has apparently 

 attended solely, or chiefly, to strata, and neglected the detritus formed 

 or deposited upon them. 



Notwithstanding this objection, we have no doubt that the essay 

 will be favourably received by botanical geographers, who find that 

 they must consider all the causes in action, whether they be strati- 

 graphical, detrital, geographical, or cUmatal. 



In the Press. 



We learn that Mr. Gosse has nearly ready a new work on the 

 Marine Natural History of Tenby and its Vicinity. 



