PREFACE TO FIRST EDITION 
THE re-arrangement of the British Lichens in the Herbarium of 
the British Museum and the incorporation of a great series of 
specimens made a revised Catalogue of these plants a necessity. 
The large number of authentic specimens from Dillenius, 
Hudson, Sowerby, Dawson Turner, T. Taylor, Salwey, Mudd 
and Leighton contained in the Herbarium supplied material for 
determining the species of these lichenologists which does not 
exist elsewhere ; while the extensive series of British Lichens, 
including the collections of Buddle, E. Forster, R. Brown, 
Carroll, Piggot, Holl, Crombie and Larbalestier, made it possible 
to determine with certainty the geographical distribution of the 
species within the British Islands. 
The Rev. J. M. Crombie, M.A., undertook the preparation 
of a Monograph based on these materials. This volume contains 
descriptions of half the known British species. The remainder 
(consisting of the Lecidei, Graphidei, Pyrenocarpei, Peridiei 
and Myriangiacei) is so advanced that it may be expected to 
appear in 1895, and will contain a complete index to the genera. 
and species of the whole work. 
WILLIAM CARRUTHERS. 
March 1894. 
