xlii INTRODUCTION. 



them. This is a difficulty which arises also in consulting some 

 printed Floras, such as those of Tonbridge and Yarmouth, in 

 whiclrthe advisability of arranging the localities by their counties 

 has been overlooked. 



For sake of brevity the surnames only of botanists are 

 printed, very seldom with any prefix of title or designation. 

 The quarter line of available space would necessitate a resort to 

 this abbreviation in many instances ; hence it is made the rule 

 for all. An occasional inconvenience attends the practice, in 

 cases of the same surname being common to two or more 

 botanists. Generally, when such is the case, the locality will 

 indicate the true personal identity. 



The Nos. prefixed to the names of counties, or substituted 

 for them in the case of plants held introduced or to be excluded, 

 are the same as shown on the map. The lines of separation, 

 which are taken to divide the larger counties into two or 

 (seldom) more vice-counties, cannot be sufficiently made out on 

 the small map ; and it may be useful to repeat their description 

 from the fourth volume of the original * Cybele Britannica,' 

 where it was adapted to the maps of England and Scotland, 

 published under the auspices of the * Society for the Diffusion 

 of Useful Knowledge.' 



" In thus subdividing the counties any natural peculiarities 

 were taken, or even well-marked lines traceable on maps, or 

 findable on the actual ground; such as water-sheds, roads, 

 canals, rivers, &c. West and East Cornwall are separated by a 

 line traced along the high road from Truro, through St. Columb, 

 to the inland extremity of Padstow Creek ; at the two ends 

 of this line, the salt-water completing the division. South and 

 Xorth Devon are separated by an imaginary line, adapted to the 

 water-shed ; commencing at the Tamar, about midway between 

 Tavistock and Launceston ; passing over the ridge of Dartmoor, 

 and joining the western canal at Tiverton. South and Xorth 

 Somerset are separated by a line along the river Parret, from 



