PREFACE. 
VU 
of supposing that they have found one of the plants de- 
scribed in a foreiga Flora, -when in reality they have only 
gathered a variety of some well-known British plant. The 
risk of falling into such errors renders it necessary to con- 
sult such works as those of Alessrs. Boreau and Jordan with 
great caution, lest we should be misled by descriptions, most 
accurate, indeed, but often rather those of individuals than 
species. Amongst plants so closely allied as are many 
of those called species in some continental works, it is 
scarcely possible to arrive at a certain conclusion without 
the inspection of authentic specimens. 
The Author takes this opportunitj- of returning most 
sincere thanks to his botanical friends and correspondents 
(far too numerous to record by name) for the great assist- 
ance they have rendered to him by the communication of 
valuable suggestions, observations, and specimens. 
The present edition has been carefully revised thi'ough- 
out, so as, if possible, to keep pace with the rapidly advan- 
cing knowledge of British plants ; the descriptions of several 
of the more difficult genera, and the S)jno2}sis of the Natural 
Orders, have been remodelled. A concise Glossary o f the 
terms used in this book is also added. 
In accordance with the wishes of several gentlemen who 
have favoured the Author with advice, many EngKsh names 
are inserted. All the genera and species could not be thus 
named, owing to the absence of any recognized English 
terms which have been applied to them. It does not seem 
desirable to invent or adopt new English names, known 
only to botanists, for the few genera which have them not, 
the Latin name being sufficient in those cases, and better in 
the original than in an Anglicized form. 
As the portability of this volume is perhaps its most 
valuable quality, the Author cannot accede to the wishes 
of some young botanists by prefixing a short Introduction 
