78 III. INTRODUCED SPECIES. 



natural vegetation, that they would undoubtedly be re- 

 garded as true natives, in the absence of the geographico- 

 historical evidence to the contrary. — Mimulus luteus has 

 become thus well established in many places, both in 

 England and Scotland. — Impatiens ftdva is perfectly esta- 

 blished in the county of Surrey, in dotted lines of several 

 miles long; and perhaps through spreading along the 

 course of the Thames river, it is becoming established 

 also in Middlesex. — Gnaplial'mm mat garitaceum, a plant 

 of rapid increase by its underground suckers, has been 

 pronounced native in Britain by several botanists, on 

 faith of its apparent wildness in some places ; though the 

 correctness of this idea is denied by others, who assert 

 that it was originally introduced from America. — Lysi- 

 machia ciliata is stated to be likewise establishing itself 

 in various spots, and with sufficient semblance of wild- 

 ness to lead to mistakes, were its transatlantic origin not 

 certain. — The remarktibly rapid increase and diifusion of 

 the recently observed Anacharis alsinastrum (Udora cana- 

 densis) is familiar to all British botanists of the day, 

 though the j)lant was hardly known to any of them a 

 quarter of a century ago. — CEnotliera biennis is less per- 

 manent, though become a half-wild weed in many spots. 

 — Barharea prcBCOx is now rather supposed than certainly 

 known to have been brought originally from America. — 

 Erigeron canadense is occasionally seen about our way- 

 sides, on rubbish heaps, and in cultivated ground ; al- 

 though, as implied by its specific name, this jilant also is 

 supposed to have been brought from America into Eu- 

 rope, where it is now abundantly diffiised in the southerly 

 latitudes, having a summer temperature warmer or longer 

 than that of Britain. — The very imperfectly established 

 Oxcdis stricta, and the locally well-estabHshed Spartina 

 alternijlora, are both suspected to have also come from 



