68 EXPLANATIONS OF THE FORMULA. 



there will unavoidably be much in the pages of his own 

 work, which is either imperfect or erroneous. The series of 

 volumes is intended to comprise a condensed record of 

 very numerous facts, themselves selected or generalised 

 from tens of thousands of other special facts ; and this con- 

 densation cannot be accompUshed without errors and over- 

 sights. All knowledge is progressive ; and each depart- 

 ment of science demands the time and exertions of many 

 labourers, in ascertaining and recording its facts, in com- 

 paring and generalismg them. 



As in our earhest Floras, much was faulty or omitted, 

 and left for after correction; so, in the earliest Cybele, there 

 will doubtless be found many errors and blemishes for sub- 

 sequent removal or rectification. Should the Cybeles ever 

 become as numerous as the Floras, the wiiting of one may 

 then be found a task of no greater thought or difficulty, 

 than the writing of a new Flora may now be found. But 

 even at the present day, after pubhcation of so many pre- 

 decessors, the writing of a new British flora is still a task 

 of some labom'. May not the author of this volume, there- 

 fore, justifiably plead the scope and laboriousness of his 

 own undertaking, almost the first of its kind, in extenu- 

 ation of any imperfections which may appear therein ? * 



* I should feel indebted to botanists, who may discover any species in 

 those provinces which are left blank (that is, distinguished only by an 

 ' *,' in place of a no. in the line which shows the area of the species) if 

 they would kindly communicate the information. And the request may 

 be extended to any other information, calculated to supply omissions, or 

 to correct errors in this work ; which can be accomplished, probably, by a 

 Supplement. But mere repetitions of localities, already ascertained and 

 published, are only inconvenient additions to the bulk of my notes, with- 

 out being- any addition to the amount of knowledge. There is a sort of 

 egotistical tendency in beginners in any study, to suppose that what is 



