4 INTRODUCTION 



In the common names there is much confusion and duplication. 

 We have herein given one common name for each species in so far as 

 such are known to us, choosing the one most common or most appli- 

 cable when there were several. 



To illustrate the use of the keys let us take the common large-leaved 

 maple. Beginning on page (7) with the Key to Families, compare 

 A with AA ; evidently this maple falls under AA. Compare the 

 next letter (C) under AA with its double (CC) ; this maple goes to 

 CC, which refers to the Key to the Dicotyledons on page (10). 

 There compare A with AA, to find it goes to A ; then the first letter 

 (B) under A with its double (BB), tracing it to B, which refers to 

 Group 3, p. II. There trace through letters in like manner to the 

 family ACERACEAE, page 148. Comparing the plant with the family 

 description, whose chief characteristics are in italics, it is found to 

 agree. Since there is only one genus (ACER) in this family, no key 

 is necessary, and it follows directly. To the right of it is the common 

 name of the group, Maple. Comparing the plant with the genus 

 description, short in this case, it is found to agree. Under it compare 

 A with AA, tracing it to A ; compare then B, BB, BBB, finding it 

 goes to BB. Then follows W. C. E., which gives its distribution 

 (see abbreviations, p. 5) ; then follows A. macrophyllum, the scien- 

 tific name. In this A. is the abbreviation of the genus name, ACER ; 

 and macrophyllum is the species name. " Large-leaved Maple " fol- 

 lows, and is the common name of this particular maple. 



That the book is free from errors is not a reasonable hope on account 

 of the great amount of detail of fact and arrangement. We would be 

 glad to have our attention called to errors that they may be corrected 

 in future editions. 



T. C. FRYE, 

 GEO. B. RIGG. 



