162 
Nancy T. Burbidge. 
higluM' coiu'eiitrntions of mineral yaltSj one must hesitate befon' placing all 
the responsibility of such a change on to the biotic factor. It is e(iually 
possible that cliniati(' cycles may be an important factor. 
In the northern part of the shrublaml cadgibuts are replaced by Acacia 
^(dicina and Acacia biveno^^a. Small drainage channels in this country are 
bare of \‘egetation and meander through the samphire for a mile or so. 
Thi'oughout this shrubland stock water can be obtained at no great depth. 
Wooroo \V('1I on the Stock Route* and about three miles iidand from Wooroo 
('r(*ek is an (*xample. When visited in duly the water level in this well was 
about twelve* feet from the surface. This Avell is on the site of an old 
aboriginal soak. Other w(*lis in the zone vary in de])th but no figures are 
available*. On the coastal ]>lain, gre)und water is commonly too salt for stock 
while in the spinifex country the* Avater though deeper down is, in most cases, 
classed as “good stock water.’’ 
I>. S })inij'e.v PimUni. 
The name “spinifex” is used locally for all species of Triodia; “pindan” 
is a native word Avhich is used for the desert country by the ])astoralists. 
This zone* can be* subdivid(*d as folloAVs - 
( a ) Ti'ansitiona! ])has(' 
(])) Triodia ])hase. 
( c) VJccfrachnc ])ha^e. 
(a) The transitional phase is particularly clear along the Anna Plains 
fi'ontage. It commences Avith a line of MeJaienca trees on the edge of the 
treeless grey loam plain. The ground flora, includes small annuals such as 
Sporobolus aiistralasicus and Kragro^stis Dielsil Avith occasional bushes of 
Trianthema tnrgidifolia. AVhere the loam changes to the red sand the liora 
also changes and Eragro:^tis eriopoda, Crotalaria Cnnninghamii, and Po- 
lavisia icosandra re])lace the above mentioned species. This phase gives Avay 
to a dense zone of Melaleuca lasiandra and Acacia transluceyis, Avhieh are 
both .^'hrubs about three to five feet high, Avith occasional clumps of Triodia 
pnujjens and Eragrostis eriopoda. After this the cadgibuts disappear and 
the area can no longer be classed as transitional. 
There aia* certain variations of the transitional phase. In some places 
there is a band of Acacia salidna in others the Acacia trauslucens band is 
missing. The change-over is narroAv and the transitional phase may only 
be ten or 15 yards in depth. In other places it extends up to 50 but 
this is not often. 
(b) and (c) The spinifex ])indan has tA\'o definite phases. In the first 
the pindan form of Triodia p)(ngeni^ is associated Avith a stunted form of 
Bauhinia CunnhigJanuii. In the second Triodia is rej)laced }>y a similar 
grass Plectrachne Schiri:ii and Bauhinia is replaced by small trees such as 
DoUchandrone heieroph ffUa and Eacadgptus zggophglla. 
The first of those phases is the nearer to the coast. Its inland boundary 
is not very definite and the phase varies in depth. The Plectrachne coun- 
tiy apparently runs out into the desert proper. It extended inland as far 
as flu* authoi* trav(*ll(*d, i.t*., to a distance* of fifteen miles from the coast 
at WTdlal. According to re]>ort it extends along tlu^ Rabbit Proof Fence at 
h^t as far as the 121 degree* meridian. 
