I. INTRODUCTORY REMARKS. 



This monograph has resulted from a suggestion made to the writer in 

 the spring of 1880 by a member* of the Committee on Publications of 

 the Philosophical Society of Washington, relative to the preparation of 

 a revised catalogue of the plants of this vicinity. While there now 

 exists a provisional catalogue, containing most of the species which 

 have been collected or observed by botanists during the past six or 

 seven ye&rs, it consists of so many small annual accretions, due to con- 

 stant new discoveries, and contains withal so many blemishes and im- 

 perfections incident to its hasty compilation and irregular growth, that 

 it has ceased in great part to meet the demands of the present time. 

 The elaboration of a systematic catalogue of the local flora was uot, 

 however, at the outset at all contemplated, but merely the i)resentation 

 of certain notes and special observations on particular species, which 

 had been made in the course of some nine years of pretty close atten- 

 tion to the vegetation and somewhat varied and exhaustive field studies 

 in this locality. The flowering-time of most species here is much earlier 

 than that given in the manuals, and is, moreover, in many cases, very 

 peculiar and anomalous, rendering it important to collectors, as well as 

 interesting to botanists, to have it definitely stated for a large propor- 

 tion of the plants. It being thus necessary to extend the enumeration 

 so far, it was thought that the remainder might as well be added, thus 

 rendering it a complete catalogue of all the vascular plants known to 

 exist here at the present time. To these has been appended the list of 

 Musci and Hepaticcc prepared by the late Mr. Kudolph Oldberg for the 

 Flora Columbiana, which is inserted unchanged, except in so far as was 

 required to make it conform strictly to the work of Sullivant, which has 

 long been the standard for this country. 



' Prof. Cleveland Abbe. 



