SOME AMERICAN COLONISTS. 225 



nature of its distribution here — only along the extreme 

 western belt of the JJritish Isles, where the coast lies 

 fully exposed to the long wash of the Atlantic — it must 

 have reached our shores by some such casual accident 

 as those which have peopled oceanic islands, like the 

 Azores, with their scanty fauna and flora. Its seeds 

 must have clung to the legs of wading birds blown east- 

 ward before a northern cyclone, or else its roots must 

 have been torn up entire and cast upon some shelving 

 Irish coast by westerly winds. Similarly, in a few Con- 

 nemara pools, as well as in two or three Continental 

 stations, another pretty little American water-plant, 

 classically named the naiad, has long grown in isolated 

 colonies, cut off by the Atlantic from the main body of 

 its race in Massachusetts and Labrador. A beautiful 

 small white orchid, too, distantly allied to our common 

 English lady's-tresses, abounds all over the eastern half 

 of North America ; but in Europe it is known only 

 in a few bogs in county Cork, where the ardour of 

 modern botanists is rapidly putting an end to its brief 

 European career. This case presents some features of 

 peculiar interest, because the Irish specimens seem to 

 have been settled in the country for a very long period, 

 sufficient to have set up an incipient tendency towards 

 the evolution of a new species : for they had so far 

 varied before their first discovery by botanists that 

 Lindley considered them to be distinct from their 

 American allies ; and even Dr. Bentham originally so 

 classed them, though he now admits the essential 

 identity of both kinds. The blue Bermuda grass-lily, 

 again, a common and extremely graceful American 

 meadow-weed, is found in one place only in Europe ; 



