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Description
Densely caespitose, the culms robust, simple, 40-50 cm tall,
glabrous and glaucous; leaf-sheaths ciliate at the orifice, blades long,
flat except for the setaceous-convolute apex, prominently nerved, scabrous
above, 2-3 mm broad, the older leaves becoming curved or twisted. Panicle
long and narrow, 12-15 cm long, not dense, pale; the branches long and
erect, the lower branches distant. Spikelets pale. Glumes sub equal, glabrous,
one-nerved or keeled, narrow, scarious, acuminate or mucronate, 11-15 mm
long, the lower scabrous on the keel. Lemma narrow, convolute, 5-6 mm long
(including the callus), glabrous or scabrous towards the apex, the callus
densely silkyvillous; awns arising from the simple, spirally twisted,
non-articulate column continuous with the summit of the lemma and 5-7 mm
long, the awns very slender, sub equal, 15-30 mm long (Gardner, 1952).
Distribution
Throughout central and northern Australia in Mitchell grass
grassland and on heavy soils.
Altitude range
250-300 m.
Rainfall requirements
It occurs in the under 500 mm rainfall belt in western Queensland
associated with Astrebla spp. in grassland. It responds to light falls
of rain better than Astrebla spp.
Drought tolerance
It has a shallow root system and is less drought resistant
than Astrebla spp., but better than Dichanthium sericeum and Digitaria
spp. (Purcell & Lee, 1970).
Soil requirements
It thrives on grey-brown and black alkaline cracking clays.
Seedling vigour
Its seeds germinate and establish earlier and later than Mitchell
grass (Astrebla spp.), but both species have the same temperature range
for germination.
Vigour of growth and growth
rhythm
It remains greener into the autumn than Mitchell grasses.
Response to defoliation
It will not stand heavy grazing and is not common in pastures
stocked with horses unless the grazing is exceptionally light.
Grazing management
It should be heavily stocked if possible, or burnt or slashed
to prevent it seeding.
Response to fire
Burning and heavy stocking have no differential effect on the
persistence of the grass (Purcell & Lee, 1970).
Latitudinal limits
23-25°S.
Natural habitat
Semi-arid open grassland.
Economics
Aristida latifolia is regarded as an undesirable species in
the Mitchell grass (Astrebla) grasslands of western Queensland. Its three-awned
seed when present in wool increases processing costs and results in lower
wool prices. The seeds also work their way into the muscle of sheep. Growth
and production of young sheep are impaired markedly. A. latifolia became
increasingly important in the late 1950s when there was a succession of
dry years. There is need for research into the auto ecology of this grass
and the general grazing management. Ploughing will destroy it, but in areas
where it is most abundant, ploughing is a costly operation.
Further reading
Purcell & Lee, 1970.
Animal performance
The young growth is lightly grazed by sheep, but it is generally
ignored in favour of more palatable grasses.
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