III. INTRODUCED SPECIES. 93 



might believe that both species occur under similar con- 

 ditions, and that they are thus equally entitled to be 

 called natives ; namely, on faith of the second term and 

 form of expression used, " inundatal " and " damp places," 

 in addition to cu,ltivated ground. But if he should look 

 to the English Flora, with the eyes of M. De Candolle, 

 he must pronounce the P. Persicaria to be undoubtedly 

 native ; while he should hold the P. Icqiathifolium as evi- 

 dently introduced, and even still very imperfectly natu- 

 ralised. 



The English Flora is a publication of older date (1824 

 — 1828) than those chiefly referred to in the Geographie 

 Botanique for ascertaining the actual condition of plants 

 in Britain, But it will be easy to prove that very recent 

 authors, up to the date of M. De CandoUe's own volumes, 

 have followed no regular rule or principle in giving such 

 indications. The annexed two series of indications 

 (pages 94, 95) are taken from the third edition of Babing- 

 ton's Manual of British Botany ; a work frequentljs and 

 not undeservedlj^ quoted in the Geogi'aphie Botanique. 

 The third edition is the one immediately preceding the 

 date of M. De CandoUe's great work. The first of the 

 two series contains the names of twenty-five species 

 which are considered by M. De Candolle to have been 

 introduced into Britain, more or less certainly so ; and in 

 his view only few of them ought even yet to be held fully 

 naturalised. The second series consists of an equal 

 number of species, the nativity of which is unquestioned 

 by English botanists, except in very few instances ; and 

 in the questioned instances M. De Candolle has decided 

 more or less confidently in favour of their nativity. By 

 taking these fifty species in pairs, as numbered, it will be 

 seen that their situations of growth are described in 

 almost the same manner for the (presumed) Introductions 



