08 BULLETIN OF THE 



Hydrangea arborescens occasionally has the outer circle of petals 

 expanded as in cultivation. 



Rudbechia fulgida has been found with all its rays tuoular but of 

 the usual length. 



Statistical View of the Flora. 



In order to present a clear view of the general character of the 

 vegetation of the District of Columbia and the adjacent country, 

 I have made a somewhat careful analysis of the large groups and 

 families, and comparison of them not only with each other, but with 

 the same groups and families in larger areas and other local floras. 

 The general results are presented below. 



It is important to remark that in all enumerations, it is not 

 simply the number, of species, as at present recognized, but the 

 number of different plants, (species and varieties,) that is employed. 

 The reason for doing this is that in very many cases, well marked 

 varieties are eventually made species, and if two plants really differ 

 there is little probability that they will ever be merged into one 

 species without that difference being indicated by some difference of 

 name. The aim has therefore been to take account of the number 

 of plants without regard to the manner in which they are named. 



The whole number of vascular plants now known to this flora, 

 as catalogued in the list appended to this paper, is 1249, and these 

 belong to 527 different genera, or about 2J species to each genus. 

 These are distributed among the several systematic series, classes, 

 and divisions, as follows : 



Groups. Genera. Species and 



varieties. 



Polyptelas 174 356 



Gamopetalse 169 389 



Total Dichlamydeae ... 343 745 



Monochlamydeae (Apetalce) 47 124 



Total Dicotyledons 390 869 



Monocotyledons 112 331 



Gymnospermse (Coniferse) 4 7 



Total Phsenogamia 506 1,207 



Cryptogamia 21 42 



Total vascular plants 527 1,249 



