11. 
Charles Austin Gardner, 
however, remarkably well defined. One crosses it at Goongarrie to the north 
of Kalgoorlie ; it runs exactly past Mt. Singleton, very close to Mt. Jackson, 
and it is intercepted again between Pindar and Wurarga, Exactly what 
happens to the east of Goongarrie is not definitely known, but the southern 
boundary reaches the coast at Shark Bay. Travelling towards the mulga 
bush we find that the Eucalypt/us shrubs and trees become more and more 
scarce, except in the sand, the species of Acacia become more prominent, and 
finally we enter into a region where the genus becomes dominant, the species 
being shrubs 3-7 metres high, with rigid glaucous phyllodes. 
I have already mentioned the fact that the species of the Eremea ex- 
hibit a marked epharmonic development. Acacia gives us a case in point. 
The common jam tree of the south-western savannah woodland {Acacia 
acuininata) has green phyllodes 7-25 cm. long and 4-7 mm. broad, in the 
typical form ; in loamy soils it develops as a shrub with narrower phyllodes, 
but still green and flat. As we a])]3roach the mulga country, this shrubby 
form becomes more and more common in the loamy soils, its phyllodes 
gradually becoming narrower with the increasing aridity, until finally, in 
the mulga bush it merges into Acacia Burhittii, witli terete or only slightly 
flattened phyllodes, and smaller flower spikes. This gradual transition 
may be studied anywhere between Mullewa and Meekatharra ; at the former 
station we have typical A. acuminata, and at Meekatharra in the loamy soil 
of watercourses we have typical Acacia Burkittii. A similar graduation 
may be seen between Eucalyptus p>yriformis and E. Kingsmillii. The same 
holds true for a number of plants, and this is now'here more evident than in 
the genus Eremophila, particularly between E. Gilesii and E. foliosissima ; 
but numerous examples could be given, and the above should suffice to il- 
lustrate the point. This epharmonic development is indeed carried out to 
such an extent in the Mulga country that ultimately, amongst the woody 
plants only two or three types of growth form and foliage remain. In general, 
with but few exceptions, the broad-leaved plants are either covered with a 
close indumentum of stellate or floccose hairs, or are heavily coated with 
resin. The glabrous leaved shrubs have narrow erect or pendulous leaves 
which all assume the same form, and the branching habit is much the same 
throughout. 
The Acacia species are of three types : Those with piimate leaves in- 
habiting the watercourses ; those with green pungent })hyllodes of the 
‘"Curara” type with a similar habitat ; those with erect or drooping rigid 
glaucous phyllodes — ^the true “mulga” plants — and those with pendulous 
flat green phyllodes, e.g., A. quadritnargvnea. 
Next in importance to the species of Acacia are the species of Eremophila, 
wliich number about one hundred. No other genus in the province exhibits 
such diversity of form. The large handsome blossoms are short-lived, and 
in many species the calyx becomes enlarged and coloured after anthesis. 
While some conform in their growth form to the general plan, others are 
widely branched with large resinous leaves. They remain of enormous 
physiognomic importance within the formation, and occur mostly in the 
sandy or stony soils, the genus being perhaps the most typical of all Eremean 
genera. 
The distribution of Eremophila is interesting. By far the greater number 
of the species of this genus are found in M^estern Australia, and although 
some are plants of the heavier soils, by far the greater number are psam- 
mophytes or lithophilous. This together with the fact that the genus is 
fairly well represented in the littoral areas of the South- A\'est, and also on 
the south and western heaths, suggests that it has developed from this pro- 
