The Vegetation of Western Aostralia. 
xia. 
In a young country such as Western Australia, there are many oppor- 
tunities for the botanist and, although botanical investigation of necessity 
rests on the foundation of systematic work conducted in the arid environment 
of the herbarium, there are many vital problems which can be solved only in 
the more inspiring atmosphere of the field. Given this necessary systematic 
basis, many are the avenues of approach which are opened up for scientific 
research which, because of the almost virgin condition of so much of the 
terrain, of^er possibilities denied to workers in the less fortunate older lands. 
Phytogeographical research in Western Australia may be said to have 
commenced with the publication of Diels’ Die Pflanzenwelt von West- Austr alien 
(1906). The foundations, however, were laid down by Sir Joseph Dalton 
Hooker in 1859, by the publication of his classic Introduction to the Flora of Tas- 
7nania, in which he propounded certain theories regarding the origin and 
affinities of the Australian flora, and gave floristic analyses which are invalu- 
able for students today. Diels, who visited Western Australia in 1901 and 
1902, dealt only with the vegetation of temperate Western Australia. It 
must be remembered, however, that at this time, means of transport were 
not what they are today, and it is surprising that he accomplished so much 
in so short a space of time. The work is, however, an indispensible one for 
all students of the plant geography of South-Western Australia. 
For over a century, in fact from the time when Dampier visited these 
shores, the flora of Australia has claimed the attention of botanists through- 
out the world. This is due to the fact that this flora, as a separate geographi- 
cal entity, ranks high amongst those floras which are remarkable for the high 
degree of endemism amongst their species. Only in South Africa, especially 
in the Cape Peninsula, and in South America, do we find anything comparable 
in the number of autochthonous species so rich in vegetative and floristic 
forms. The Cape Peninsula and South-Western Australia afford interesting 
examples for comparison. 
It is not that the families comprising the Australian flora are in them- 
selves endemic. Far otherwise : out of the total number of these there are 
but three families which are strictly endemic in Australia, with a total number 
of less than 30 species. Rather is it the number of endemic genera and species, 
which is surprisingly large in some areas (especially in the South-West of 
Australia), making up as much as 75 per cent, of the total species. There 
are a number of families and groups, on the other hand, which are mainly 
Australian, that is, the greater number of genera and species are endemic 
here, but some of the genera and species also occur in other lands, or, there 
are conjunctive genera and species present in these remote areas. These 
furnish important evidence, for they stand today as indisputable proof that 
tliese widely dispersed areas had at one time a close relationship, if not a 
common origin. The presence of these groups and species in countries like 
America and Africa, explain two important facts : (a) that the Australian 
continent was not always isolated, and that (b) the isolation has been of suf- 
ficient duration to enable the distinctive elements of the Australian flora to 
make a peaceful and progressive evolution free from any external influences, 
resulting in a specialised flora with a degree of endemism rare in other con- 
tinents. 
II. THE ELEMENTS OF THE AUSTRALIAN FLORA. 
The geographical isolation of the Australian continent, its uniform topo- 
graphy, and the resultant gradation of climatic areas which range from tropi- 
cal to temperate, are the main considerations which must be borne in mind 
when we approach the study of the vegetation of Western Australia. Separated 
