16 FLORA OF WASHINGTON AND VICINITY. 



C. mirea, meant G. JIavula, which is now abundant, but omitted by them. 

 Their Arabis stricta might have been A. hirsuta or A. patens, which are 

 now rare, though it was more probably a form of A. laevigata, as they 

 seemed to be 'especially fond of drawing nice distinctions and expressing 

 them by synonyms. Varieties, however, were scarcely recognized by 

 them, the trinomial theory being then in its infancy. I might thus 

 proceed to discuss all their supposed errors, but the reader can do this 

 for himself, as the species now known, but which are not contained in 

 the Prodromes, are designated in tlie general catalogue below. 



The second and third classes, amounting together to 16 per cent, of 

 the alleged excess over the present flora, consist also of errors, but errors 

 which it is much less easy to palliate. It is natural to wish to make as 

 large a showing as i^ossible, and the temptation to insert into a cata- 

 logue everything which by any construction can be claimed to belong 

 there is rarely resisted. To show that this propensity still exists, it 

 may be remarked that of the 1,054 species enumerated in the x)relimi- 

 nary catalogue of the j)lants of this vicinity, published by the Potomac- 

 Side Naturalists' Club in 1870, 89, or about 8J per cent., are now admitted 

 by all not to have been seen here at that time, and have never been 

 found by anj' one since, although nearly three hundred other species 

 have since been added to the flora. This is certainly not a scientific 

 method to proceed upon, and, as already remarked, the present attempt 

 aims to eliminate to a great extent this source of error. 



The 81 species constituting the fourth class remain, therefore, the 

 only ones to which any special interest attaches, and for the determina- 

 tion of which the present somewhat laborious analysis of this ancient 

 document has been undertaken. For these the botanists of our time 

 should make diligent search, and perchance a few of them may still be 

 found. Assuming that they no longer exist, they do not simply repre- 

 sent the number of plants that have disappeared from our flora during 

 an interval of fifty years. This could be only on the assumption that 

 the Prodromus was a complete record of the flora at the time. This it 

 certaiuly is not. The aggregate number, exclusive of synonyms or du- 

 plicated names, which it contained was, as we saw, 800. We now 

 identify, counting as was then done, species and varieties, 1,249 distinct 

 forms. While, no doubt, many of these have been freshly appearing, 

 while others have been disappearing, still, from the considerations above 

 set forth, it is highly probable that the indigenous flora of 1830 was 

 considerably larger than that of 1880, and may have reached 1,400 or 



