III. FLORA OP BRITAIN. 391 



■wide variety of S. umbrosa ,- but living plants of it kindly- 

 sent by Mr. J. G. Baker, do not confirm tliis idea. If of 

 garden origin only, without native habitat, it is the com- 

 mencement of an apparent species, as well entitled to be 

 deemed a species on its external characters, as are great 

 numbers of those described for species in books, and 

 seldom or never questioned. 



These are not all of the plants which have been 

 described in Britain, either as species or as well-marked 

 varieties, and have not been strictly identified with those 

 of any other country. They are only to be taken as 

 selected examples of the dubious species (but true varie- 

 ties, if not true species) hitherto not certainly ascertained 

 beyond the British Isles. The spurious species of Salix, 

 Rosa, Rubus, Mentha, Cerastium, and Hieracium, hitherto 

 described only on British specimens, can count as no- 

 thing in the main question, whether the British Isles do 

 now possess any true species or distinct races peculiar to 

 themselves, and therefore reasonably presumed not to 

 have been derived from other countries stiU in existence. 



The generally admitted link of connexion between the 

 American and (British floras, seen in the Eriocaulon 

 septangulare, has been alluded to above. — Also, the con- 

 nexion, mistakenly supposed to have been established, 

 through an identity of Spiranthes gemmipara with Spi- 

 ranthes cernua. — Some very small doubt may still attach 

 to the Alopecurus alpinus, of Scotland ; whether this spe 

 cies is strictly identical with that of arctic America, and 

 also with that of arctic Europe usually so named. — 

 Anacharis Alsinastrum seems to be only an imported 

 American Udora, now too abundantly established in 

 England, and needlessly re -named here; likely also 

 identical with the Udora said to have become established 

 in Prussia and West Russia. — Sisyrinchium anceps is 



