Plants of
South Australia
Amphibromus pithogastrus
Plump Swamp Wallaby-grass
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Regional Species Conservation Assessments per IBRA subregion.
Least concern
Near threatened
Critically endangered
Data deficient
Coober Pedy
Mount Gambier
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Common names

Plump Swamp Wallaby-grass


Amphibromus from the Greek 'amphi' meaning double and 'bromus' a grass genus, referring to the spikelets resembling those of the genus Bromus. Pithogastrus from the Greek 'pithos' meaning a large earthenware pot and 'gaster' meaning belly, referring to the swollen lemmas at maturity.

Distribution and status

Restricted to a few sites in the southern Mount Lofty Ranges in South Australia, growing in seasonally damp areas. Also found in New South Wales and Victoria. Native. Endangered in South Australia. Extremely rare in the other States. The SA Seed Conservation Centre collected and banked more than 1,500 seeds for this endangered grass in 2016 with the support of Natural Resources Adelaide & Mount Lofty Ranges. Further collections of this endangered grass will be attempted in 2017 from the two other known historic locations in the Mt Crawford region.
Herbarium region: Southern Lofty
AVH map: SA distribution map (external link)

Plant description

Erect perennial grass to 1 m tall with open sparse and drooping habit. Leaf-blades flat or involute to 20 cm long and 5 mm wide, scaberulous to glabrous. Panicle to 25 cm long. Spikelets to 15 mm long. Glumes similar, thinner than fertile lemma. Lower glume lanceolate, membranous, keeled; 1-keeled, 3�5 -nerved. Upper glume elliptic to 7.3 mm long, membranous, keeled; 1-keeled, 5�7 -nerved. Flowering between October and December. Fruits are lemma to 7.5 mm long, without keel and with 7-nerves. Lemma apex toothed, 1 -awned. Awn dorsal, 9�16 mm long, with a twisted column. Column 3�5 mm long. Seeds are yellow-brown grain to 4 mm long. Seed embryo type is lateral.

Seed collection and propagation

Collect seeds between December and January. Use hands to gently strip seeds off the mature seed spike that are turning straw colour. Mature seeds will come off easily. Alternatively, you can break off the whole seed spike. 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. From three collections, the seed viability was average to high, ranging from 70% to 100%.

Seeds stored:
LocationNo. of seeds
(weight grams)
of plants
Collection number
Collection location
% ViabilityStorage
BGA80 (0.1 g)1513-Dec-2009KHB347
Southern Lofty
BGA660 (0.82 g)154-Jan-2011KHB347
Southern Lofty
BGA1,500 (3.78 g)80+29-Dec-2016KHB347
Southern Lofty
1-Nov-2017 -18°C
BGA9,800 (26.6 g)50+20-Dec-2018KHB347
Southern Lofty
20-Jun-202375%-18°C, -80°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.
Germination table: