INTRODUCTORY ESSAY. 
Preliminary Remarks. 
The Island of Tasmania does not contain a vegetation peculiar to itself, nor constitute an indepen- 
dent botanical region. Its plants are, with comparatively few exceptions, natives of cxtratropical 
Australia; and I nave consequently found it necessary to study the vegetation of a great part of that 
vast Continent, in order to determine satisfactorily the nature, distribution, and affinities of the 
Tasmanian Flora. 
From the study of certain extratropical genera and species in their relation to those of Tasmania, 
I have been led to the far more comprehensive undertaking of arranging and classifying all the 
Australian plants accessible to me. This I commenced in the hope of being able thereby to extend 
our knowledge of the affinities of its Flora, and, if possible, to throw light on a very abstruse subject, 
viz. the origin of its vegetation, and the sources or causes of its peculiarity. This again has induced me 
to proceed with the inquiry into the origin and distribution of existing species ; and, as I have already 
treated of these subjects in the Introduction to the New Zealand Flora, I now embrace the opportu- 
nity afforded me by a similar Introduction to the Tasmanian Flora, of revising the opinions I then 
entertained, and of again investigating the whole subject of the creation of species by variation, with 
the aid of the experience derived from my subsequent studies of the Floras of India and Australia in 
relation to one another and to those of neighbouring countries, and of the recently published hypo- 
theses of Mr. Darwin and Mr. Wallace. 
No general account of the Flora of Australia having hitherto been published, nor indeed a com- 
plete Flora of any part of it, I have been obliged, as a preliminary measure, to bring together and 
arrange the scattered materials (both published and unpublished) relating to its vegetation to which 
I had access. Those which are published consist of very numerous papers relating to the general 
botany of Australia, in scientific periodicals, and appended to books of travel, amongst which by far 
the most important are Brown's ' General Remarks, Geographical and Systematical, on the Botany 
of Terra Australis,' published in the Appendix to Captain Flinders' Voyage, now nearly half a century 
ago ; Allan Cunningham's Appendix to Captain King's Voyage, which appeared in 1827 ; Lindley's 
Report on the Swan River Botany ; and Mueller's, on the Tropical Botany of Australia. There are 
also some special essays or descriptive works on the Floras of certain parts of the continent : of 
