80 



assigned his plant a specific character, which is as applicable 

 to other species, and he illustrated his meaning by quoting a 

 synonym of Gronovius, which instead of being a Crataegus is 

 Amelanchier Canadensis. Succeeding Botanists could not 

 therefore tell what he meant, and the second name they gave 

 to the plant of Linnaeus ought we think to have been retained. 



There is a large, and often, we doubt not, a very 

 proper reduction of species, which in many cases have 

 been created upon garden seedlings, whose peculiar features 

 have been owing to domestication. Too much care however 

 cannot be exercised in this respect, or a greater evil will 

 result from confounding different species under one common 

 name, than from separating mere varieties as distinct species. 

 In the genus Calycanthus for example, C. Icevigatus is com- 

 bined with C. fioridus and C. glaucus. But unless there is 

 some positive evidence that the first of these plants is the 

 same as the other two its great dissimilarity of appearance 

 would make it desirable to keep it distinct. Again, in join- 

 ing CEnothera serotina with Q^.fruticosa, two more widely 

 different plants are united, than CE. glauca and fruticosa 

 which are separated. 



We might make some similar observations upon genera, 

 such as the union of Geum with Sieversia, Bartonia with 

 Mentzelia, and of CEnothera with Godetia, while Horkelia is 

 separated from PotentUla, Vachellia from Acacia, and Cerasus 

 from Primus ; but these are matters of less importance. 



In conclusion it is only necessary to call attention to the 

 supplementary matter appended to the volume. It shows 

 the result of Dr. Gray's examination of European herbaria, 

 so far as the earlier orders are concerned, an advantage he 

 had not enjoyed when the first and second parts of the work 

 went to press. Nothing can indicate more clearly than this 

 supplement the unwearied diligence with which Dr. Gray 

 studied the important materials then for the first time placed 

 before him. 



The authors may be congratulated upon having proceeded 

 so far in their publication, which, it is not too much to say, 

 is one of the most important additions to systematical botany 

 that has appeared for many years. 



