The Subscriber takes this mode of expressing his thanks to Mr. 

 Wm. M. Canby of Wilmington, Delaware, for much assistance in the 

 compilation of the Catalogue of Flowering Plants, and to Professor 

 D. C. Eaton of New Haven, Connecticut, for the Catalogue of the 

 Vascular Cryptogamia, the most complete one, it is believed, yet 

 published. For all imperfections, which are numerous enough, as 

 the list of Errata (to which all are especially directed) partially 

 shows, he must hold himself alone responsible. It is requested 

 that other errors which may be detected by those who use the 

 Catalogue, may be communicated, in view of another possible edition. 



HORACE MANN. 



Cambridge, July 1, 1868. 



