PREFACE TO SECOND EDITION 
Tue long interval of time between the publication of the two 
Parts of the Monograph of British Lichens rendered necessary 
the preparation of a new edition of Part I. as soon as possible 
after the completion of Part II., and fortunately Miss Lorrain 
Smith was able to undertake the work. 
The present volume covers the same ground as the first 
edition of Part I. by the Rev. J. M. Crombie, but has been 
completely re-written; much new material has been incor- 
porated, and considerable alterations in arrangement. and 
classification have been made. It thus forms an independent 
work companion to Part II., by the same author, issued in 1911. 
By the addition of an Appendix, in which are contained 
those Orders that under the accepted scheme of arrangement 
would have been included in Part II., the two Parts are 
correlated ; together they form a complete modern presentment 
of the British Lichens. Miss Smith has also added, in the form 
of an Introduction, a general account of the Lichens. 
The small blocks in the text illustrating the genera have 
been replaced by a series of plates similar to those issued with 
Part IT. 
A. B. RENDLE. 
DEPARTMENT OF BOTANY, 
British Museum (Natura History), 
CROMWELL Roap, S.W. 
July 1918. 
