PREFACE. XI 



cultivated plants, that it would be absurd, in a work professing to 

 describe the vegetation of a country, to omit those which cover two- 

 thirds of its surface. On the other hand, those who confine them- 

 selves to strictly indigenous plants, plead the uncertainty attend- 

 ing the insertion of introduced or cultivated ones, which are daily 

 becoming more numerous, and that, if you once open the door for 

 their admission, you cannot draw the line between the local Flora 

 and the enumeration of all the species ever raised in our gardens. 

 In the present Work it has been endeavoured, after the example of 

 our best Floras, to steer a middle course as the most useful to the 

 amateur, although, certainly, not the most correct were the object to 

 supply data for the Physical Geographer. Plants evidently culti- 

 vated are omitted from the Flora, but those most likely to be met 

 with are usually shortly alluded to under the families or genera to 

 which they respectively belong. Introduced plants which appear 

 to have permanently established themselves, and spread beyond the 

 locality where they were first sown or accidentally deposited, such 

 as Hewett Watson designates as colonists, are generally included, 

 whilst such temporary visitors as only reappear when the causes of 

 their introduction recur, the aliens of Hewett Watson, are in most 

 cases omitted. An exception is, however, made in favour of corn- 

 field weeds, many of which have now become so widely spread over 

 the globe that it is difficult to say where they are really indigenous 

 or natiiralized. In some instances it would appear that the whole 

 of the land they would have origmally inhabited is now in a state of 

 cultivation; and if omitted from one Flora on the ground of their 

 being meVely sown with the crops, they must, for the same reason, 

 be rejected from almost every other one. 



There is another class of doubtful inhabitants of our coimtry 

 which have obtained insertion in our Floras, from having been said 

 to have been once found by some zealous explorer, although no one 

 has as yet succeeded in confii-ming the discovery. These are now 

 frequently rejected on the supposition that some mistake had arisen 

 in the identity of the species, or in the record of the circumstances 

 under which it was found. Whenever this appears to have been the 

 case, such species, as weU as those which, although once natives, are 

 now known to be extinct within our limits, are omitted in the present 

 Work ; but, on the other hand, the stations of some species, on the 

 outskirts of their general area, are really very limited, and they may 

 only be met with accidentally, at long intervals. In deciding on the 



