Plants of
South Australia
Austrostipa petraea
Gramineae
Flinders Range Spear-grass
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Regional Species Conservation Assessments per IBRA subregion.
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Etymology

Austrostipa from the Latin 'auster' meaning south and the genus Stipa, referring to the genus being allied to Stipa but restricted to Australia. Petraea from Latin meaning ''belonging to rocks', referring to its habitat, of growing in rocky places.

Distribution and status

Endemic to South Australia and found in the northern and southern Flinders Ranges, growing in rocky places. Native. Rare in South Australia.
Herbarium regions: Flinders Ranges, Eyre Peninsula, Northern Lofty
NRM regions: Eyre Peninsula, Northern and Yorke, South Australian Arid Lands
AVH map: SA distribution map (external link)

Plant description

Tufted perennial grass to 1.5 m high, with a short rhizome; unbranched culms and silky hairy nodes. Leaves glabrous below, pubescent or scabrous above, not sharp-tipped, with blades inrolled, to 50 cm long and 1.5 mm wide; leaf sheaths glabrous; ligule to 1 mm. Inflorescence compact or open panicle to 40 cm long, with more than 8 spikelets. Glumes to 15 mm long, sub-equal. Flowering between September and December.

Key to this species: lemma apex with long lobes (teeth) 1.5-2.5 mm; panicle with more than 8 spikelets; culm unbranched; leaves not sharp-tipped; lemma hairs orange; ligules short 0.1-1 mm. Flinders Ranges endemic on rocky sites Fruits are brown elliptic lemma to 9.5 mm long, with a smooth surface covered in orange hairs; coma to 3 mm; callus long sharp to 1.5 mm; awn with 1 distinct bend to 60 mm long, with column to 25 mm long. Seeds are yellow-brown narrow ellipsoid grain to 4 mm long within the lemma. Seed embryo type is lateral.

Seed collection and propagation

Collect seeds between October and January. Use your hands to gently strip the seeds (lemma) off the mature fruiting spike, those that are turning golden brown. Mature seeds will come off easily compare to the immature seeds that remain on the spike. Alternatively, you can break off the whole fruit spike to allow some of the seeds to mature further. Place the seeds/spike in a tray and leave to dry for two weeks. No further cleaning is required if only seed collected. If seed spikes collected, use hand to strip off the mature seeds. Store the seeds with a desiccant such as dried silica beads or dry rice, in an air tight container in a cool and dry place. Viability of grass seeds could be very variable, depending on time of seed collections and seasonal conditions. From one collection, the seed viability was average, at 70%.

Seeds stored:
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LocationNo. of seeds
(weight grams)
Number
of plants
Date
collected
Collection number
Collection location
Date
stored
% ViabilityStorage
temperature
BGA 
MSB
1,350 (5.52 g)
1,350 (5.52 g)
50+5-Dec-2005TEE2
Eyre Peninsula
9-Aug-200670%-18°C
Location: BGA — the seeds are stored at the Adelaide Botanic Gardens, MSB — the seeds are stored at the Millennium Seed Bank, Kew, England.
Number of plants: This is the number of plants from which the seeds were collected.
Collection location: The Herbarium of South Australia's region name.
% Viability: Percentage of filled healthy seeds determined by a cut test or x-ray.