The Vegetation of Western Australia. 
xli. 
The main area of the Northern Province is connected with the Fortescue- 
De Grey region by a narrow neck of Pindan country in the vicinity of Wollal. 
The Fortescue-De Grey region, which centres round the Hamersley Range 
has been referred to previously as an area which is almost an “ island ” in 
the Eremea. The whole of this area is not well known phytogeographically, 
but the extensive development of savannah, the climatic conditions, and the 
existence of many vestiges of the Indo-Malayan Element, render its inclusion 
within the Province necessary. There are, however, several important 
changes. The deciduous species no longer exist, with the single exception 
of Brachychiton australe, but the prevalence of such plants as Owenia, Livistona^ 
Atalaya, Bauhinia, Dichrostachys, and a number of others, including certain 
lithophytes and mesophytic herbs, shows that this country has many re- 
semblances to that of the north. In the savannah. Sorghum, Eulalia, Chryso- 
pogon, Heteropogon, Iseilema, and Astrebla remain as important constituents — 
plants which are almost totally absent from the Eremea. Here again the savan- 
nah is restricted to the alluvial soils, merging into a type of Pindan and the 
Triodia steppe. Along the rivers and in the declivities of the Hamersley Range 
we find such plants as Astrotricha, Ficus, Terminalia, and Clerodendron, whilst 
the Rubiaceae and Scrophulariaceae, together with several megathermic 
Compositae, remain in sufficient numbers to be regarded as important. The 
actual western boundary of the Northern Province near the Ashburton River 
is not known, but occurs near Mardie m the west, and includes Red Hill, while 
to the east it extends to Marble Bar and Nullagine. Whether or not the 
Province extends to the south of the Hamersley Range is not known with 
certainty. 
2. THE SOUTH-WEST PROVINCE. 
The South-West Piovince is distinguished floristically by the rich develop- 
ment of the Australian and Antarctic Elements. This c'e/elopment is most 
powerfully expressed towards the cusps of its tringular-crescentic area of 
distribution, both in the north, between the Hill River and the Murchison 
River, and in the south-east between the Phillips River and Israelite Bay. 
There is, indeed, a close connection between the plants of these two widely 
separated areas, as for example the restricted distribution of Phymatocarpus, 
Conothamnus, and certain species of Eucalyptus and Adenanthos, as well as 
certain close affinities in a few groups such as Conostylis and Anigozanthos. 
Both areas represent the richest areas in species and forms in the entire pro- 
vince. It is also noteworthy that these two areas are precisely the regions 
where the climatic and epharmonic gradients are the sharpest, and thus com- 
petition between Eremean and southern forms least possible of extension. 
Other characteristics of the South-West Province are the predoininence 
of sclerophyllous shrubs in every formation, either as undergrowth in the 
forest and woodland, or crowding the heaths. The floristic wealth of these 
heaths is probably unparallelled an;ywrhere else on the earth. Important, 
too, is the paucity of herbaceous plants, particularly the grasses, although 
the Cyperaceae, Restionaceae, Haemodoraceae, Liliaceae, and Compositae 
make up to some extent for this deficiency. When one considers the facility 
with which certain exotic grasses establish themselves, as for example in 
the tuart country, this paucity of the indigenous grasses is difficult to under- 
stand. It may be the story of the warfare which is supposed to exist between 
woodland and grassland, and that the climatic conditions favour the develop- 
ment of trees and shrubs, or it may be a question of the biotic factor, or of 
species migration, for the greater number of the indigenous grasses, with 
the exception of a few such as Festuca, Danthonia, Stipa, and Amphipogon^ 
appear to be of palaeotropic derivation, and have not been able to obtain a foot- 
