NOTICES OF BOOKS. 85 



A, long and extremely interesting article is devoted to the naturaliza- 

 tion of plants imported from great distances into different parts of the 

 world, as Europe, the United States, India, etc.; but it is impossible, 

 within our limits, to go into this. With regard to the tropical and 

 subtropical species especially, the limits of the species are often so 

 disputed, that the data upon which the arguments are founded have a 

 different value in the opinions of different naturalists; for that special 

 knowledge of all the conditions, physical and others, under which the 

 plants are found in countries with which the author is not intimately 

 acquauited, being necessarily wanting, he is obliged to rely upon 

 sources of information of extremely different value. That some of our 

 own best local botanists differ as to the indigenous or exotic origin of 

 many of our common English plants, is notorious; but the wrong con- 

 clusions that must arise from this source of inevitable error, are, thanks 

 to M. de CandoUe's greater general acquaintance with European botany 

 and with the physical features of Europe and its flora, considerably 

 reduced. The lists given, and the discussions that accompany them, 

 are however of the greatest value, not onl}' from the immense amount 

 of valuable information brought together, but from the skilful manner 

 in which they are arranged for analysis. Upon such a subject, an 

 author can, in the present state of knowledge, be a pioneer only, and 

 as such, M. de Candolle has here done his duty admirably. 



Under the discussion upon tropical plants which are common to 

 Asia, Africa, and America, and have probably been transported from 

 one of these countries to the others, a list of the principal ones are 

 given, which, as being of great value, we here quote. 



J. Tropical Species, now common to Asiay Africa, and America^ hut probably trans- 

 ported from the Old World to the New, or from the New to the Old. 



Argemone Mexicana, L. Cassia occidentalis, L. Hyptis spinigera, Lam, 



? Cleome pentaphylla, DC: „ Fistula, Z. Leucas Marti nicen sis, Br. 



Mollugonudicaulis,j3,/V«-?/.? Crotalaria incana, Z. Leonotis nepetoefolia, Br. 



Ureua lobita, i. „ retusa, L. Chenopod. ambrosioides, L, 



? Sida spinosa, Z. Rhizophora Mangle, L. Cyathula prostrata, Blume. 



? » stipulata, Cav, Ageratnm couyzoides, Z. AJtemanthcra sessilis, Br, 



„ cordifolia, Z. Bideas pHosa, Z. Amaranthus spinosua, Z. 



Hibiscus esculentus, Z. SphenocleaPongatiun],i)6'. Euxolog riridis, 3Ioq. 



? „ tiliaceus, Z. ScEevola Lobelia, Z. „ caudatns, Moq. 



Zoruia diphylla. IJyptis pectinata, Foit. PAchyranthesfruticosa, Lam. 



>. var.glochidiata,ff^>/M. „ brevipes, P^^V. ? »> aspcra, X. 



