82 ^^OTICES OF BOOKS. 



Plantes des Indes. Plantes du Cap de Bonne-Esperance, Acacias et 

 Proteacese de la Nouvelle-Hollande. 



Nota 



Michaux 



par L. C. Richard^ font partie de V Herbier-generaL 



NOTICES OF BOOKS. 



Geographte Botanique RaisonniSe, ou Exposition des Faits prin- 

 cipaux et des Lois concernant la Distribution Geograpliique des Plantes 

 de Vepoque actuelk; par M. Alph. de Candolle, etc- 3 vols. 8vo- 



Paris. 



{Continued from p, 64.) 



The second volume of M, de CandoUe's Work opens with a continua- 

 tion of the Second Book, which is devoted to Geographical Botany, as 



• H 



contradistinguished from Botanical Geography, and with Chapter 8, 

 which is devoted to the changes that affect the localities inhabited by 

 species, or in other words, that affect the distribution of species. The 

 subject of Naturalization here holds a prominent place, and M. de 

 Candolle commences with defining the term as he understands it.. A 

 species he considers to be completely naturalized which is found to be, 

 to all appearance, in the same relative conditions as the indigenous 

 species amongst which it is growing : that is to say, it grows and mul- 

 tiplies without the agency of man ; it appears constantly ; it is more 

 or less abundant in the localities that suit it ; and it has existed for 

 many years, during some of which the climate has been exceptional. 

 The proof therefore of a plant being naturalized must rest upon histo- 

 rical evidence. 



On the other hand, a plant is not to be considered as naturalized, 

 which, when introduced by the agency of man, only propagates itself 

 by roots, without ripening its seeds, or at least spreading by means of 

 them. To this category the Robinia Pseudacacia, Rlms^ and Jilanthus 

 belong, in Europe. 



Many difficult questions as to what plants are to be called natural- 

 ized, arise from the complexity of the phenomena depending indirectly 

 upon man's agency; thus many species are only known to inhabit cul- 

 tivated ground, and other artificial localities, whilst another and a large 



