Nancy T. Bubbidge. 
99 
Group (a) includes the following : — 
(i) A large domed tussock up to a metre or more in height and about 
the same in diameter. The general habit is dense. The sheaths are very 
resinous and on older culms the resin is dried to a white incrustation. The 
leaves are dark green, the blades about 20-25 cm. long and scabrid along 
the margins which are spread apart. The panicle is large and 50—70 cm. 
higher than the tussock. The panicle branches are long, the lower ones 
bearing 6-10 spikelets, each of the latter bearing more than six florets. 
This is a coarse form which is eaten in the young stages. Later the 
sheep turn to it only in case of necessity. It is common on the plains along the 
De Grey River and southwards to Marble Bar. 
(ii) Dark green tussock smaller than the preceding to which it approaches 
closely. The leaves are usually very scabrid but there are plants with smooth 
margined leaves. It differs in lacking the white incrustation on the older 
portions, in its smaller size and its smaller panicle whose branches bear 4-5 
spikelets. It is a very resinous form. 
It is, perhaps, the most common form of soft spinifex. It was found by 
the author on all inland stations visited. It is, in some places, subject to 
variation due to habitat. For example, at Mount Edgar Station, south-east 
from Marble Bar, it grew as a small compact tussock on the higher rocky 
ground anti as a more vigorous larger tussock in the hollows. It is eaten 
in the young stages and also later except where there is a high proportion 
of dead leaves. 
(i ii) Low flat tussock about 30 cm. high and up to 2-3 metres in diameter. 
The central or older portion commonly dies off. In this case the dried culms 
disintegrate and blow away. The panicle is short, 10— 20 cm. long and com- 
pact, i.e., the branches arise close together. 
This form was well developed in the country adjacent to the Coongan 
River, a tributary of the De Grey. It appeared to be fairly palatable to 
sheep. 
(iv) Small dense tussock 30-40 cm. high with very yellowish green leaves. 
This was an easily recognisable form in the field. The leaf blades are softer 
than in other forms and the blades are closed so that the leaf appears terete. 
The panicle is again short and only about 20-30 cm. higher than the tussock. 
The spikelets are very squat and ovate. 
Common along the De Grey plains. It occurs in small areas amongst 
(i) and (ii) from which it can be easily separated. 
fv) Hill Spinifex. The tussocks on the rocky slopes are very short 
culmed. The leaf blades are variable and* in the gullies may grow to more 
than 30 cm., though usually they are 15-20 cm. long. The panicle has fewer 
spikelets, which are narrower and with the lemmas more imbricate. The 
glumes are rather scarious, not indurate, and the lobes of the lemmas are 
shorter than in the plains forms. The plants are less resinous. 
Found on all hilly country in the Pilbara area. It is apparently an 
ecotype, being restricted to its habitat. The hills on which it grows are 
stony, arid, and barren. 
(vi) Coastal Spinifex. The plants are characterised by their long leaves, 
30-50 cm. long, thin and wiry as in (iv). The general habit is a dense central 
butt with a loose mass of surrounding culms. The panicle has spikelets 
which are consistently smaller than those of the inland forms. The smaller 
