FLORA OF WASHINGTON AND VICINITY. 43 



fication the figures of the Catalogue of the Plants of Illinois, 1876, pre- 

 pared by Mr. Harry X. Patterson, as summarized iu the preface. In 

 the former case the introduced species are inckided, but the varieties 

 seem to be excluded. In the latter case, ^s stated by Mr. Patterson, 

 the introduced species are excluded, as are also, doubtless, the varieties. 



For the flora of the Southern United States east of the Mississippi 

 (1:^0. 5), which I have compiled from Dr. Chapman's Flora of the Southern 

 States, indigenous species are alone taken, in order to make it conform 

 as nearly as possible to the flora of the Northeastern United States 

 (No. 4). 



The lilants collected by the Fortieth Parallel Survey (No. 7), and those 

 collected on Lieutenant Wheeler's Survey (No. 8), are introduced rather 

 as a means of contrasting the eastern with the western portions of the 

 continent than as a jiroper ijart of the comparative botanical statistics 

 of this vicinitj". The former of these collections was very thoroughly 

 and carefully made by an energetic and experienced botanist, Mr.Sereno 

 Watson, and derives its chief value from this fact. It embraces, how- 

 ever, a territory having a somewhat special character from a botanical 

 point of view, viz., in general terms, the Great Basin between the Eocky 

 Mountains and the Sierra Nevadas, and the High Plateaus and mountains 

 immediately adjacent (Wasatch, Uintas, Sierras), with a restricted range 

 north and south. The data are taken from the summary of the work 

 prepared by Mr. Watson, and found on page xlv of the report. The 

 collections embraced in the report of Lieutenant Wheeler's Survey, on 

 the other hand, were made by numerous collectors, some of them ama- 

 teurs, and were scattered over a very wide extent of Western territory, 

 including Colorado, New Mexico, Utah, Arizona, and Nevada, and con- 

 tinued through five years of exploration. They may be taken, there- 

 fore, to represent with some correctness the general character of our 

 Western flora, exclusive of the Pacific coast. The facts given are 

 derived from the " Table of Orders " on page 379. In both cases varie- 

 ties are excluded. 



For the remaining floras comi)ared in the table (Nos. 1, 2, and G), to 

 avoid recompilation, the data previously used are repeated, species and 

 varieties, including also introduced plants, being emx)loyed. As already 

 intimated, however, this difference in the basis of compilation of differ- 

 ent floras, appl;ydng as it does to the several groups and to the aggre- 

 gate alike, cannot materially affect the percentages as computed. 



