78 REVIEWS. 



relatives, or who may cultivate North American shrubs or flowering plants. 

 It forms a complete flora of all the northern states east of the Mississippi, and 

 includes, to the south, the extensive territories of Virginia and Kentucky. 

 M This southern boundary," its author tells us, " coincides better than 

 any other geographical line with the natural division between the cooler 

 temperate and the warm-temperate vegetation of the United States ; very 

 few characteristically southern plants occurring north of it, and those only 

 in the low coast of Virginia, in the Dismal Swamp, &c. Our western limit, 

 also, while it includes a considerable prairie vegetation, excludes nearly all 

 the plants peculiar to the great western woodless plains which approach our 

 borders in Iowa and Missouri. Our northern boundary, being that of the 

 United States, varies through about five degrees of latitude, and nearly 

 embraces Canada proper on the east and on the west ; so that nearly all the 

 plants of Canada East on this side of the St. Lawrence, as well as of the deep 

 peninsula of Canada West, will be found described in this volume." 



The number of species described is 2,928, divided as follows : — Dicoty- 

 ledons, 1,713 ; Monocotyledons, 638 ; Ferns and Filicoids, 75 ; Mosses and 

 Hepaticse, 502. The remaining Cryptogamous orders are omitted. The 

 descriptions, without being needlessly prolix, are sufficiently full to enable a 

 student readily to ascertain the name of a species ; and he is further assisted 

 by the arrangement of the type — the most important or striking feature of 

 each species being italicised, in the manner now so frequently and so use- 

 fully introduced into local floras. Synoptic tables of the genera are given 

 under each natural order, by which means the labour of ascertaining the 

 genus to which a plant belongs is greatly lessened ; and, for the use of 

 young botanists, an artificial key to the natural orders is prefixed. The 

 genera of the Cryptogamia are ably illustrated in fourteen excellent litho- 

 graph plates — a most important aid to the student unacquainted with the 

 systematic arrangement of these tribes. The descriptions of the Mosses 

 and Hepaticae are from the pen of Mr. Sullivant, one of the ablest of living 

 muscologists, " who has," says Dr. Gray, " included in this edition all the 

 species of Musci and Hepaticce known to him as natives of any part of the 

 United States east of the Mississippi, and has sedulously elaborated the whole 

 anew; not only laying a broad foundation for a knowledge of North 

 American Muscology, but furnishing botanical students with facilities for the 

 study of these two beautiful families of plants, such as have never before 

 anywhere been afforded in a book of this kind." We cordially endorse this 

 well-deserved encomium. 



It is needless to speak of the manner in which Dr. Gray has executed 



