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The book is "aimed to include all the generally accepted 

 native and naturalized trees north of the latitude of the northern 

 boundary of North Carolina, and east of the Rocky Mountains." 

 The key as drawn up is based on the normal typical leaves, 

 "such as we consider distinctive of the various species and by 

 which we recognize them," . . . "the average specimens on a 

 mature tree, not those on very young or excessively vigorous 

 shoots." Fruit characters are also included in connection with 

 some of the trees "either as essential or accessory parts of the 

 key; though many species can readily be traced without referring 

 to the fruits." The book is intended to supplement the more 

 extensive publications on native trees, — "to enable one to have 

 in a compact and systematic form an aid in the identification 

 of trees by a study of their leaves". The value of this little 

 book to teachers lies in its availability as an aid for field work for 

 older secondary students and for college students. Work on 

 the identification of plants has a disciplinary value much higher 

 than the amount of time usually devoted to it would seem to 

 indicate. Trees offer probably by far the best medium for such 

 work because of their size and usually the corresponding saliency 

 of their distinctive characters, and also because of the greater 

 interest attaching to them than to less conspicuous plants. Of 

 course the value of any particular key for class work will depend 

 in the end upon its workability in actual service, but those who 

 are familiar with Mr. Hough's Handbook will not question his 

 very high qualifications for the preparation of a practicable key. 

 As a matter of fact an examination of his treatment of some of the 

 difhcult genera shows that it is as good as would be expected. 

 The differentiation of the species of oak is particularly good. 

 One omission there is which detracts somewhat from the ready 

 usefulness of the key — this is the failure to cite any of the varying 

 different distributions of the trees. So for the oaks, a resident 

 of Massachusetts seeking to identify a red oak would have to 

 decide between four species, one of which is native farther south 

 but which, at least in leaf characters, the red oak may at times 

 resemble. For example I have in mind two large oaks with 

 large flat-saucered acorns growing in the Litchfield hills in 



