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The following Keys are designed to facilitate the reference of any plant to its proper Order; 

 and it is hoi)ed that the one may so supplement the other that in most cases little difficulty 

 will be found. A synopsis is likewise given of the genera under each order, and of the species 

 in most of the larger and more difficult genera. 



All the more important synonymy is cited, including references to the principal figures. 

 The geographical range is indicated as nearly as our piesent knowledge permits, but the 

 habitiits of many of the rare or local species will doubtless be much extended as the Slate 

 la more thoroughly explored. Additional species will also be discovered, and the descriptions 

 of the known species here given may prove in some cases to be defective or erroneous. In- 

 formation in regard to any additions or corrections is solicited for an appendix to the second 

 volume, or for a future supplement. 



It has not been possible to give here, introductory to the Flora, that preliminary botanical 

 instruction which is neccs.-4ary to it.t use. To supply the need, a brief lntrodu(;tion to Sys- 

 tematic Botany will probably be iuchuled in the volume which is to follow, and reference 

 may be made meanwhile to the ordinary text-books upon the subject, such as Gray's " Les- 

 sons in Botany. " 



