INTBODUOTION. 



aggregates or segregates ; excluding for the present most of the 

 varieties, along with the aliens, casuals, errors, &o. A selection 

 of the counties may be made Tdj limiting the enumeration, of 

 their names to those of counties from which the plant has been 

 reported on fair authority, as being presumably indigenous 

 there, denizens and colonists here ranking with truer natives. 

 Other counties can be sufficiently shown by their nos. only; 

 that is, those supposed to have been erroneously reported for the 

 plant, and those into which it is believed to have been intro- 

 duced by human agency alone. Those in support of which 

 the recorded authority appears to be insufficient for scientific 

 reliance will be left out or grouped with the former. Any 

 botanist who has glanced at the array of enclosed nos. in the 

 recently printed ' Supplement ' above mentioned, will have seen 

 how numerous a portion of the recorded habitats there came 

 under one or other of the two categories, — the non-indigenous 

 ( ) or the supposed errors [ ] . 



These preliihinary observations on the end sought, and the 

 difficidties in attaining it, will facilitate an understanding of the 

 methods resorted to for that purpose ; — here resorted to, not 

 because they are the best possible, but because they appear to 

 be practically best under the circumstances. Except in the 

 cases of the commoner plants, all the counties wiU be enu- 

 merated by name and no. under each species treated; that is, 

 all which have been found recorded on authority sufficiently 

 reliable, and without being too exacting in the test ; a change 

 to nos. only being made for sake of brevity under the conditions 

 mentioned above. 



It is to be distinctly understood, however, that the enumera- 

 tion of counties does not undertake or profess to be absolutely 

 exhaustive of all records of the kind. On the contrary, it is to 

 be understood as including only those which came under the 

 compiler's consideration while writing the ' Cybele Britannica ' 

 and its Compendium ; with the further addition of others 



e 



